Showing papers on "Breakdown voltage published in 2008"
TL;DR: In this article, the GaN-based recessed MIS-gate structure in conjunction with negative polarization charges under the gate allows the high threshold voltage, whereas the low on-state resistance is maintained by the 2D electron gas remaining in the channel except for the recessed gate region.
Abstract: This letter reports normally-off operation of an AlGaN/GaN recessed MIS-gate heterostructure field-effect transistor with a high threshold voltage. The GaN-based recessed MIS-gate structure in conjunction with negative polarization charges under the gate allows us to achieve the high threshold voltage, whereas the low on-state resistance is maintained by the 2-D electron gas remaining in the channel except for the recessed MIS-gate region. The fabricated device exhibits a threshold voltage as high as 5.2 V with a maximum field-effect mobility of 120 cm2/Vmiddots, a maximum drain current of over 200 mA/mm, and a breakdown voltage of 400 V.
383 citations
TL;DR: In this article, the authors present the following hypothesis for the mechanisms leading to improved properties of polymer nanocomposites with metal oxide nanoparticle fillers: the inclusion of nanoparticles provides myriad scattering obstacles and trap sites in the charge carriers' paths, effectively reducing carrier mobility and thus carrier energy.
Abstract: Polymer nanocomposites with metal oxide nanoparticle fillers exhibit enhanced electrical breakdown strength and voltage endurance compared to their unfilled or micron filled counterparts. This paper presents the following hypothesis for the mechanisms leading to improved properties. The inclusion of nanoparticles provides myriad scattering obstacles and trap sites in the charge carriers' paths, effectively reducing carrier mobility and thus carrier energy. The result is homocharge buildup at the electrodes, which increases the voltage required for further charge injection due to blocking by the homocharge. The hypothesis is supported by electroluminescence, pulsed electro acoustic analysis, thermally stimulated current measurements, a comparison of AC, DC, and impulse breakdown, as well as absorption current measurements, in silica/crosslinked polyethylene matrix composites with supporting evidence from titania/epoxy composites.
321 citations
TL;DR: In this article, a novel method for fabricating trench structures on GaN was developed and a smooth non-polar (1100) plane was obtained by wet etching using tetramethylammonium hydroxide (TMAH) as the etchant.
Abstract: A novel method for fabricating trench structures on GaN was developed. A smooth non-polar (1100) plane was obtained by wet etching using tetramethylammonium hydroxide (TMAH) as the etchant. A U-shape trench with the (1100) plane side walls was formed with dry etching and the TMAH wet etching. A U-shape trench gate metal oxide semiconductor field-effect transistor (MOSFET) was also fabricated using the novel etching technology. This device has the excellent normally-off operation of drain current–gate voltage characteristics with the threshold voltage of 10 V. The drain breakdown voltage of 180 V was obtained. The results indicate that the trench gate structure can be applied to GaN-based transistors.
214 citations
TL;DR: In this paper, a high electron mobility transistor (HEMT)-compatible power lateral field effect rectifier (L-FER) with low turn-on voltage is demonstrated using the same fabrication process as that for normally off AlGaN∕GaN HEMT, providing a low-cost solution for GaN power integrated circuits.
Abstract: A high electron mobility transistor (HEMT)-compatible power lateral field-effect rectifier (L-FER) with low turn-on voltage is demonstrated using the same fabrication process as that for normally off AlGaN∕GaN HEMT, providing a low-cost solution for GaN power integrated circuits. The power rectifier features a Schottky-gate-controlled two-dimensional electron gas channel between the cathode and anode. By tying up the Schottky gate and anode together, the forward turn-on voltage of the rectifier is determined by the threshold voltage of the channel instead of the Schottky barrier. The L-FER with a drift length of 10μm features a forward turn-on voltage of 0.63V at a current density of 100A∕cm2. This device also exhibits a reverse breakdown voltage (BV) of 390V at a current level of 1mA∕mm and a specific on resistance (RON,sp) of 1.4mΩcm2, yielding a figure of merit (BV2∕RON,sp) of 108MW∕cm2. The excellent device performance, coupled with the lateral device structure and process compatibility with AlGaN∕GaN...
179 citations
TL;DR: In this article, the channel layer substitution of a wider bandgap AlGaN for a conventional GaN in high electron mobility transistors (HEMTs) is an effective method of enhancing the breakdown voltage.
Abstract: The channel layer substitution of a wider bandgap AlGaN for a conventional GaN in high electron mobility transistors (HEMTs) is an effective method of enhancing the breakdown voltage. We demonstrated a remarkable breakdown voltage enhancement in these AlGaN channel HEMTs. The obtained maximum breakdown voltages were 463 and 1650V in the Al0.53Ga0.47N∕Al0.38Ga0.62N HEMT with the gate-drain distances of 3 and 10μm, respectively. This result is very promising for the further higher power operation of high-frequency HEMTs.
163 citations
TL;DR: In this paper, an atomic-layer deposition (ALD) was used to achieve an ultra-high capacitance density of 440 at a breakdown voltage VDB > 6 V on a silicon substrate containing high-aspect-ratio macropore arrays.
Abstract: ldquoTrenchrdquo capacitors containing multiple metal-insulator-metal (MIM) layer stacks are realized by atomic-layer deposition (ALD), yielding an ultrahigh capacitance density of 440 at a breakdown voltage VDB > 6 V. This capacitance density on silicon is at least 10times higher than the values reported by other research groups. On a silicon substrate containing high-aspect-ratio macropore arrays, alternating MIM layer stacks comprising high-k Al2O3dielectrics and TiN electrodes are deposited using optimized ALD processing such that the conductivity of the TiN layers is not attacked. Ozone annealing subsequent to each Al2O3 deposition step yields significant improvement of the dielectric isolation and breakdown properties.
146 citations
TL;DR: In this paper, an enhancement of punchthrough voltage in AlGaN/GaN high-electron-mobility transistors was presented by increasing the electron confinement in the transistor channel using an AlGAN buffer-layer structure.
Abstract: In this paper, we present an enhancement of punchthrough voltage in AlGaN/GaN high-electron-mobility-transistor devices by increasing the electron confinement in the transistor channel using an AlGaN buffer-layer structure. An optimized electron confinement results in a scaling of punchthrough voltage with device geometry and a significantly reduced subthreshold drain leakage current. These beneficial properties are pronounced even further if gate-recess technology is applied for device fabrication. Physical-based device simulations give insight in the respective electronic mechanisms.
143 citations
18 May 2008
TL;DR: In this article, an AlGaN HFET with a high breakdown voltage of over 1.8 kV and a maximum drain current of 120 A was demonstrated on 4-inch Si substrates.
Abstract: In this paper, we successfully demonstrate an AlGaN HFET with a high breakdown voltage of over 1.8 kV on 4 inch Si substrates. In order to obtain the high breakdown voltage and to improve the crystalline quality of GaN layers, a thick GaN epitaxial layer including a buffer layer with a total thickness of over 6 mum was grown. The breakdown voltage and the maximum drain current were achieved to be over 1.8 kV and 120 A, respectively. Furthermore, the suppression of the current collapse phenomenon is examined. The on-resistance is not so significantly increased up to the high drain off-bias-stress of 1.0 kV.
133 citations
TL;DR: In this paper, the authors used Weibull and Gaussian distributions to estimate the breakdown voltage of synthetic esters, a natural ester and a mineral oil to evaluate the compatibility of ester oils with existing transformer insulation.
Abstract: Recent decades have seen the rapid and successful deployment of ester oils as transformer dielectrics. When evaluating the compatibility of ester oils with existing transformer insulation designs, it is essential to not only compare the mean breakdown voltages of the oils, but also to consider the role of dispersion and thus the withstand voltage levels (with the acceptable breakdown likelihood). Insulation designers sometimes estimate the withstand voltage of mineral oil from the dispersion of the data, assuming that the breakdown voltages of the oil follow a parametric distribution. However, there is a lack of discussion as to whether this method would be suitable for estimating the withstand voltages of ester oils. This paper uses samples of breakdown voltages of a synthetic ester, a natural ester and a mineral oil to analyze their distributions, and discusses the applicability of using Weibull and Gaussian distributions to estimate the withstand voltages of the esters. It is found that the distributions of ester breakdown voltages, in particular the lowest breakdown voltage, are similar to those of mineral oil. Consequently there is evidence that from the ac withstand voltage point of view the tested esters are compatible for the use in power transformers.
114 citations
TL;DR: In this paper, the temperature dependent heterojunction behavior of n-type zinc oxide (ZnO) nanorods and ZnO∕p-Si diodes was explored.
Abstract: This work explores the temperature dependent heterojunction behavior of n-type zinc oxide (ZnO) nanorods/ZnO∕p-Si diodes. The as-grown ZnO nanorod structures on ZnO coated p-Si substrates are single crystalline and grown along the [001] direction. The p-n diode showed an excellent stability over the temperature range of 20–150°C due to highly doped p-type Si substrate. The turn-on and breakdown voltage of the device slightly decreased with an increase of temperature whereas the saturation current of the device increased from 0.42to0.67μA. The device behavior at different temperatures in forward as well as reverse biased conditions are studied and reported.
113 citations
TL;DR: In this article, a solar-blind AlGaN-based p-i-n photodetectors that are grown by metal-organic chemical vapor deposition on c-plane sapphire substrates are reported.
Abstract: We report on the high performance solar-blind AlGaN-based p-i-n photodetectors that are grown by metal-organic chemical vapor deposition on c-plane sapphire substrates. The dark current of the 200μm diameter devices was measured to be on the order of 5fA for bias voltages up to 10V. The breakdown voltages were higher than 200V. The responsivities of the photodetectors were 0.052 and 0.093A∕W at 280nm under 0 and 40V reverse biases, respectively. We achieved a detectivity of 7.5×1014cmHz1∕2∕W for 200μm diameter AlGaN p-i-n detectors.
TL;DR: In this article, the double Schottky barriers at the interface of n-ZnO∕SiOx∕p-Si diodes have been investigated for light-emitting Diodes.
Abstract: n-ZnO∕SiOx∕n-Si and n-ZnO∕SiOx∕p-Si heterostructured light-emitting diodes have been fabricated using metal-organic chemical-vapor deposition for a comparison study. n-ZnO∕SiOx∕p-Si heterostructures show diodelike rectifying current-voltage characteristic with low breakdown voltage, while n-ZnO∕SiOx∕n-Si heterostructures show symmetric nonlinear current-voltage behavior due to the double Schottky barriers at the interface. Both types of diodes emit light when a positive bias applied at Si side. Ultraviolet emission at ∼390nm with an orange-emission centered at ∼600nm were observed in electroluminescence spectra of n-ZnO∕SiOx∕n-Si diodes, while whitish emission centered at ∼520nm was observed for n-ZnO∕SiOx∕p-Si diodes. The emission mechanisms were discussed.
Patent•
21 Sep 2008TL;DR: In this article, a method for forming a metal/semiconductor/metal (MSM) back-to-back Schottky diode from a silicon (Si) semiconductor is provided.
Abstract: A method is provided for forming a metal/semiconductor/metal (MSM) back-to-back Schottky diode from a silicon (Si) semiconductor. The method deposits a Si semiconductor layer between a bottom electrode and a top electrode, and forms a MSM diode having a threshold voltage, breakdown voltage, and on/off current ratio. The method is able to modify the threshold voltage, breakdown voltage, and on/off current ratio of the MSM diode in response to controlling the Si semiconductor layer thickness. Generally, both the threshold and breakdown voltage are increased in response to increasing the Si thickness. With respect to the on/off current ratio, there is an optimal thickness. The method is able to form an amorphous Si (a-Si) and polycrystalline Si (polySi) semiconductor layer using either chemical vapor deposition (CVD) or DC sputtering. The Si semiconductor can be doped with a Group V donor material, which decreases the threshold voltage and increases the breakdown voltage.
TL;DR: In this article, a planar asymmetric Ni−NiO−Cr/Au thin film metal-insulator-metal (MIM) tunnel diodes were fabricated for use in an ultra-sensitive infrared detector operating at room temperature.
TL;DR: In this article, an improved bevel mesa structure and a single-zone junction termination extension (JTE) have been employed to achieve a high breakdown voltage (ges 10 kV).
Abstract: Designing and fabrication of 10-kV 4H-SiC PiN diodes with an improved junction termination structure have been investigated. An improved bevel mesa structure and a single-zone junction termination extension (JTE) have been employed to achieve a high breakdown voltage (ges 10 kV). The improved bevel mesa structure, nearly a vertical sidewall at the edge of the p-n junction and a gradual slope at the mesa bottom, has been fabricated by reactive ion etching. The effectiveness of the improved bevel mesa structure has been experimentally demonstrated. The JTE region has been optimized by device simulation, and the JTE dose dependence of the breakdown voltage has been compared with experimental results. A 4H-SiC PiN diode with a JTE dose of 1.1 times 1013 cm-2 has exhibited a high blocking voltage of 10.2 kV. The locations of electric field crowding and breakdown are also discussed.
TL;DR: In this article, a transparent all-oxide p-NiO/n-MgZnO heterojunctions were fabricated on indium-tin-oxide-coated glass substrates by sol-gel spin coating technique.
Abstract: Transparent p-n heterojunctions composed of p-type NiO and n-type MgZnO thin films were fabricated on indium-tin-oxide-coated glass substrates by sol-gel spin coating technique. The p-n junctions exhibit typical current-voltage behaviors with good rectifying characteristics, and their electrical properties can be effectively tuned by band gap engineering of n-MgZnO. With increment of Mg content in n-MgZnO layer, enlarging band gap can lead to the higher forward threshold voltage, higher breakdown voltage, and lower reverse saturation current. The electrical behaviors of the p-n junctions can be further improved by using compositionally graded n-MgZnO layer instead of single n-MgZnO layer. These results suggest that the transparent all-oxide p-NiO/n-MgZnO heterojunctions can find applications in transparent electronic devices.
TL;DR: In this paper, a novel silicon-on-insulator (SOI) high-voltage MOSFET structure and its breakdown mechanism are presented, which is characterized by oxide trenches on the top interface of the buried oxide layer on partial SOI (TPSOI) devices.
Abstract: A novel silicon-on-insulator (SOI) high-voltage MOSFET structure and its breakdown mechanism are presented in this paper The structure is characterized by oxide trenches on the top interface of the buried oxide layer on partial SOI (TPSOI) Inversion charges located in the trenches enhance the electric field of the buried layer in the high-voltage blocking state, and a silicon window makes the depletion region spread into the substrate Both of them modulate the electric field in the drift region; therefore, the breakdown voltage (BV) for a TPSOI LDMOS is greatly enhanced Moreover, the Si window alleviates the self-heating effect The influences of the structure parameters on device characteristics are analyzed for the proposed device structure The TPSOI LDMOS with BV > 1200 V and the buried-layer electric field of EI > 700 V/ mum is obtained by the simulation on a 2-mum-thick SOI layer over 2-mum-thick buried oxide layer, and its maximal temperature reduces by 19 and 87 K in comparison with the conventional SOI and partial SOI devices
TL;DR: In this article, a Si ion implantation doping technique was used to achieve sufficiently low resistive source/drain contacts, and realized the first HEMT operation with an AlGaN channel layer.
Abstract: A channel layer substitution of a wider bandgap AlGaN for conventional GaN in high electron mobility transistors (HEMTs) is one possible method of enhancing the breakdown voltage for higher power operation. Wider bandgap AlGaN, however, should also increase the ohmic contact resistance. We utilized a Si ion implantation doping technique to achieve sufficiently low resistive source/drain contacts, and realized the first HEMT operation with an AlGaN channel layer. This result is very promising for the further higher power operation of high-frequency HEMTs.
TL;DR: In this paper, the authors have presented and demonstrated the methods of estimating the limiting thermal breakdown voltages on a few nanocomposite materials used as power cable insulation, and the results show a considerable improvement in the thermal maximum voltage and other related parameters.
Abstract: With the advent of nano-particle fillers in insulating materials, the insulating materials of superior quality have come to fore. In the recent past, nanocomposite LDPE/XLPE (low density polyethylene/cross linked polyethelene) power cable dielectrics have been synthesized. A preliminary evaluation of these new class of materials seem to show that, addition of small amounts of sub-micron inorganic fillers improved the dielectric properties of the composite, in particular, the volume resistivity, and the dc breakdown strength. The thermal behaviour, for example, the stability of composites against decomposition and ensuing electrical failure, do not seem to have been addressed. In a conventional XLPE insulated cable, the average thermal breakdown strength and maximum temperature at the onset of breakdown were seen to be markedly lower than the corresponding intrinsic breakdown strength and decomposition temperature. In the present paper, the Authors have presented and demonstrated the methods of estimating the limiting thermal breakdown voltages on a few nanocomposite materials used as power cable insulation. Experimental data on the volume resistivity reported in recent literature has been used in the series of computations. Nanocomposites of LDPE doped with small amounts of nano-particles of MgO, are chosen. The results show a considerable improvement in the thermal maximum voltage and other related parameters.
18 May 2008
TL;DR: In this paper, an n-channel GaN hybrid MOS-HEMT realized on AlGaN/GaN heterostructure on sapphire substrate is described.
Abstract: We report on the experimental demonstration of a novel n-channel GaN hybrid MOS-HEMT realized on AlGaN/GaN heterostructure on sapphire substrate. This enhancement-mode MOS-gated heterojunction transistor, with 3 mum channel length and 20 mum RESURF length, exhibited a specific on-resistance as low as 20 mOmega-cm2. Simulations indicated the strong dependence of device breakdown voltage on the doping and concentration of the bottom p-GaN layer and its important role in reducing the surface electric field to suppress oxide breakdown.
TL;DR: In this paper, the breakdown voltage of atmospheric pressure helium gas between two parallel-plate electrodes was investigated from 2 to 100 MHz and it was shown that the breakdown voltages of helium gas can be reduced initially with increasing frequency due to a diminishing contribution of drift-dominated electron wall loss and then begin to increase with an increasing frequency.
Abstract: We report a detailed study of breakdown voltage of atmospheric-pressure helium gas between two parallel-plate electrodes from 2 to 100 MHz. Experimental data show that the breakdown voltage reduces initially with increasing frequency due to a diminishing contribution of drift-dominated electron wall loss and then begins to increase with increasing frequency. The latter is contrary to the current understanding that relies largely on the electron wall loss mechanism. Particle-in-cell simulation suggests that rapid oscillation of the applied voltage prevents electrons from reaching their maximum achievable kinetic energy, thus compromising the ionization efficiency and increasing the breakdown voltage.
Patent•
12 Dec 2008
TL;DR: In this article, a magnetic tunnel junction (300 ) structure was proposed to improve spin torque yield and reliability while requiring only a low temperature anneal, and the breakdown voltage was high, resulting in a favorable ratio of V c /V bd.
Abstract: A magnetic tunnel junction ( 300 ) structure includes a layer ( 308 ) of iron having a thickness in the range of 1.0 to 5.0 Å disposed between a tunnel barrier ( 306 ) and a free magnetic element ( 310 ) resulting in high magnetoresistance (MR), low damping and an improved ratio V c /V bd of critical switching voltage to tunnel barrier breakdown voltage for improved spin torque yield and reliability while requiring only a low temperature anneal. This improved structure ( 300 ) also has a very low resistance-area product MgON diffusion barrier ( 312 ) between the free magnetic element ( 310 ) and an electrode ( 314 ) to prevent diffusion of the electrode into the free layer, which assists in keeping the damping, and therefore also the switching voltage, low. With the low annealing temperature, the breakdown voltage is high, resulting in a favorable ratio of V c /V bd and in a high proportion of devices switching before breakdown, therefore improving the yield and reliability of the devices.
TL;DR: In this paper, the breakdown characteristics of the discharge in the micrometric regime were extensively studied by the theoretical approach including ion-enhanced field emission, and semi-empirical expressions for the dependence of the breakdown voltage on the gap spacing and on the pressure based on the numerical solutions of the equation that describes the dc breakdown criteria have been proposed.
Abstract: The phenomenon of field emission plays a significant role in the deviation of the breakdown voltage from that predicted by Paschen's law within the range of high electric fields. High fields obtained in small gaps may enhance the secondary electron emission and such enhancement could lead to a lowering of the breakdown voltage and a departure from the Paschen curve. In this paper, the dc breakdown characteristics of the discharge in the micrometric regime were extensively studied by the theoretical approach including ion-enhanced field emission. In addition, semi-empirical expressions for the dependence of the breakdown voltage on the gap spacing and on the pressure based on the numerical solutions of the equation that describes the dc breakdown criteria have been proposed.
TL;DR: The p-channel IGBT (p-IGBT) exhibits a transconductance that is 3 times higher than that of the 12-kV n-channel SiC IGBTs as mentioned in this paper.
Abstract: SiC bipolar devices are favored over SiC unipolar devices for applications requiring breakdown voltage in excess of 10 kV. We have designed and fabricated p-channel insulated-gate bipolar transistors (IGBTs) in 4H-SiC with 12-kV blocking voltage for high-power applications. A differential on-resistance of 18.6 mOmega ldr cm2 was achieved with a gate bias of 16 V, corresponding to a forward voltage drop of 5.3 V at 100 A/cm2, indicating strong conductivity modulation in the p-type drift region. A moderately doped current enhancement layer grown on the lightly doped drift layer effectively reduces the JFET resistance while maintaining a high carrier lifetime for conductivity modulation. The p-channel IGBT (p-IGBT) exhibits a transconductance that is 3times higher than that of the 12-kV n-channel SiC IGBTs. An inductive switching test was done at 1.5 kV and 0.55 A (~440 A/cm2) for the p-IGBTs, and a turn-on time of 40 ns and a turn-off time of ~2.8 mus were measured.
TL;DR: In this article, a breakdown mechanism of polarized semiconductors represented by GaN-based materials is presented, based on the concept of a natural super junction, which is established by the inherent material polarization.
Abstract: A breakdown mechanism of polarized semiconductors represented by GaN-based materials is presented, based on the concept of a natural super junction, which is established by the inherent material polarization. In this concept, owing to the precise matching of positive and negative polarizations of both sides of GaN and AlGaN materials, average charge concentration in the material becomes nearly zero under reverse bias condition, which realizes extremely high breakdown voltage. This model is confirmed by device simulation taking all polarization charges of GaN-based materials into account. Furthermore, experimentally fabricated GaN-based Schottky barrier diodes showed a linear increase of breakdown voltage along the anode-cathode spacing, achieving a record breakdown voltage over 9000 V.
TL;DR: In this article, the mesa-type photodiodes exhibit a responsivity at 1310nm of 0.54A/W, a breakdown voltage thermal coefficient of 1.05%/°C, a 3dBbandwidth of 10GHz, and gain-bandwidth product was measured as 153GHz.
Abstract: We designed and fabricated Ge/Si avalanche photodiodes grown on silicon substrates. The mesa-type photodiodes exhibit a responsivity at 1310nm of 0.54A/W, a breakdown voltage thermal coefficient of 0.05%/°C, a 3dBbandwidth of 10GHz. The gain-bandwidth product was measured as 153GHz. The effective k value extracted from the excess noise factor was 0.1.
TL;DR: In this article, the authors proposed a novel silicon-on-insulator (SOI) high-voltage device with a compound buried layer (CBL SOI) consisting of two oxide layers and a polysilicon layer between them.
Abstract: A novel silicon-on-insulator (SOI) high-voltage device with a compound buried layer (CBL SOI) consisting of two oxide layers and a polysilicon layer between them is proposed. Its breakdown characteristic is investigated theoretically and experimentally. Theoretically, its vertical breakdown voltage (BV) is shared by two oxide layers; furthermore, the electric field in the lower buried oxide layer of EI2 is increased from about 78 to 454 V/mum by holes collected on the bottom interface of the polysilicon. Both result in an enhanced BV. Experimentally, 762-V SOI diode is obtained. The maximal temperature of CBL SOI diode is reduced by 16.9 K because a window in the upper buried oxide layer alleviates the self-heating effect.
Patent•
11 Sep 2008TL;DR: In this paper, a bipolar type semiconductor device capable of attaining high current gain and high cut-off frequency and performing a satisfactory transistor operation also in a high current region while maintaining a high breakdown voltage performance, as well as a method of manufacturing the semiconductor devices, are provided.
Abstract: A bipolar type semiconductor device capable of attaining high current gain and high cut-off frequency and performing a satisfactory transistor operation also in a high current region while maintaining a high breakdown voltage performance, as well as a method of manufacturing the semiconductor device, are provided. In a collector comprising a first semiconductor layer and a second semiconductor layer narrower in band gap than the first semiconductor layer, an impurity is doped so as to have a peak of impurity concentration within the second collector layer and so that the value of the peak is higher than the impurity concentration at any position within the first collector layer. It is preferable to adjust the concentration of the doped impurity in such a manner that a collector-base depletion layer extends up to the first collector layer.
TL;DR: In this article, high quality δ-doped p-GaN is used as a means of improving the performance of back-illuminated GaN avalanche photodiodes (APDs).
Abstract: High quality δ-doped p-GaN is used as a means of improving the performance of back-illuminated GaN avalanche photodiodes (APDs). Devices with δ-doped p-GaN show consistently lower leakage current and lower breakdown voltage than those with bulk p-GaN. APDs with δ-doped p-GaN also achieve a maximum multiplication gain of 5.1×104, more than 50 times higher than that obtained in devices with bulk p-GaN. The better device performance of APDs with δ-doped p-GaN is attributed to the higher structural quality of the p-GaN layer achieved via δ-doping.
TL;DR: In this paper, the breakdown voltage in microgaps has been solved analytically and the derived analytical relation indicates that the DC breakdown voltage depends on the gap size d and the pressure p, particularly, rather than on the product pd.
Abstract: The field-emission–related effects play a significant role in the deviation of the breakdown voltage from that predicted by Paschen's law in the range of micrometer gaps. Beginning from a certain gap spacing, breakdown voltage diverges from the climbing curve seen in the left half of the Paschen curve. In this paper, the equation governing the DC breakdown in microgaps has been solved analytically. The derived analytical relation indicates that the DC breakdown voltage in microgaps depends on the gap size d and the pressure p, particularly, rather than on the product pd. The new theoretical expression allows key features to be identified suggesting that the inclusion of the field emission at micron and submicron gaps is necessary to describe properly the experimental data. The expression presented here can receive a wider interest due to its applicability to the breakdown voltage for a series of gases, gaps and pressures and can serve as ready-to-use guidelines for system engineers and designers.