Showing papers on "Schottky diode published in 1976"
TL;DR: In this article, the Schottky barrier was used in thin-film amorphous-silicon solar cells and the current-voltage characteristics were studied in the range from 270 to 370°K and were found to be in agreement with the diffusion theory of metal-semiconductor rectification.
Abstract: Metal–amorphous‐silicon Schottky barriers, similar to those used in thin‐film amorphous‐silicon solar cells, exhibit nearly ideal diode behavior in the dark. The current‐voltage characteristics have been studied in the range from 270 to 370 °K and are found to be in agreement with the diffusion theory of metal‐semiconductor rectification. Barrier heights, which were measured by two different methods, depend on the metal work function, and barriers as high as ∼1.1 eV are obtained with Pt films.
189 citations
TL;DR: In this paper, the properties of d.c. sputtered molybdenum-silicon Schottky diodes are described and a model is proposed which is capable of explaining most features of the observed C-V and I-V characteristics.
Abstract: The properties of d.c. sputtered molybdenum-silicon Schottky diodes are described. Although it is possible to produce near ideal characteristics when a low sputtering voltage is used for a short time, increased voltage and time lead to significant deviation from the ideal. A model is proposed which is capable of explaining most features of the observed C-V and I-V characteristics. This model assumes that sputtering damage causes donor-like traps to be created close to the semiconductor surface. It is found that an exponential distribution of traps with characteristic length in the range 10–100 A and an energy level of 0·43 eV below the conduction band is sufficient to account for the observed characteristics. The modification to the I–V characteristics is due to tunnelling through the top of the Schottky barrier where it is narrowed by the presence of the excess trapped charge.
124 citations
TL;DR: In this paper, it was shown that current transport through Schottky barriers formed by Pd on n-type silicon with a thin thermally grown oxide is sensitive to hydrogen in the ambient.
Abstract: It is shown that current transport through Schottky barriers formed by Pd on n-type silicon with a thin thermally grown oxide is sensitive to hydrogen in the ambient. It is shown that a transition from minority- to majority-carrier dominated current occurs with increasing hydrogen pressure.
115 citations
TL;DR: In this article, the electrical and optical properties of Au-n-type silicon Schottky-barrier solar cells (SBSC) have been measured and it has been shown that the value of Voc is increased by up to 38% and the maximum conversion efficiency by as much as 35% when compared with cells having no grown oxide layer.
Abstract: Measurements have been made of the electrical and optical properties of Au–n‐type silicon Schottky‐barrier solar cells (SBSC) in which the metal and semiconductor are separated by a thin interfacial oxide layer ∼10–23 A thick. Measurements of the V‐I characteristics showed that the value of Voc is increased by up to 38% and the maximum conversion efficiency by as much as 35% when compared with cells having no grown oxide layer.
110 citations
TL;DR: In this paper, the theory of MIS-Schottky barriers and their electrical characteristics is examined for its application to solar cells and it is found that the interface behavior of contacts forwardbiased by illumination is qualitatively different from that of the same contacts biased in the dark by an applied forward voltage.
Abstract: The theory of MIS‐Schottky barriers and their electrical characteristics is examined for its application to solar cells. It is found that the interface behavior of contacts forward‐biased by illumination is qualitatively different from that of the same contacts biased in the dark by an applied forward voltage. Observed increases due to the interfacial layer in the open‐circuit voltage of the solar cell cannot therefore be associated with increases in the ’’n value’’ measured for the dark current, but rather are due to the different effects of this layer on the transport properties of majority and minority carriers. The theory predicts an optimum thickness for the interfacial layer above which the short‐circuit (minority‐carrier) current decreases, and the efficiency (fill factor) is degraded.
108 citations
TL;DR: The barrier height of a Pd-CdS Schottky diode is reported to decrease markedly when exposed to hydrogen as mentioned in this paper, due to the decrease in Pd work function.
Abstract: The barrier height of a Pd‐CdS Schottky diode is reported to decrease markedly when exposed to hydrogen. This effect is believed to be due to the decrease in Pd work function. It makes a good simple hydrogen detector (even at 298 °K) over the range 500–5000 ppm H2.
103 citations
TL;DR: In this article, the formation of Schottky barriers between Si(111) 7 and group-III metals has been studied by ultraviolet photoemission spectroscopy, and a two-step empirical model is proposed for the formation.
Abstract: The formation of Schottky barriers between Si(111) 7 \ifmmode\times\else\texttimes\fi{} 7 and group-III metals has been studied by ultraviolet photoemission spectroscopy Modifications of the band bending and of the work function occur for low values of metal coverage (one to four monolayers) The "intrinsic," clean surface states are simultaneously replaced with "extrinsic" metal-related interface states A two-step empirical model is proposed for the formation of the barrier The first step is saturation of interface bonds, and the second step, critical in determining the junction properties, corresponds to the formation of a thin region with properties intermediate between that of a metal and of a semiconductor Our experiments emphasize the need for a detailed theoretical treatment of the interface chemical bonds and underline the inadequacy of "macroscopic" models for metal-semiconductor junctions
99 citations
TL;DR: In this paper, the open circuit voltage of MIS solar cells realized on n-type silicon has been investigated, and the influence of different parameters like n or ΦBn are discussed.
Abstract: The open‐circuit voltage of MIS solar cells realized on n‐type silicon has been investigated. Chemically formed and evaporated SiOx layers have been used for the insulating film. The latter has given the best results on polished samples, since Voc reached 0.55V. The influence of different parameters like n or ΦBn are discussed.
92 citations
TL;DR: In this article, the authors used backscattering of energetic 4He+ ions to study the composition and depth profile of silicide layers formed when thin nickel films evaporated on (111) and (100) silicon surfaces are heated in a nitrogen-hydrogen ambient.
Abstract: Rutherford backscattering of energetic 4He+ ions has been used to study the composition and depth profile of silicide layers formed when thin nickel films evaporated on (111) and (100) silicon surfaces are heated in a nitrogen-hydrogen ambient. In the temperature range 297 to 430 degrees C two phases are seen to form sequentially. The growth of the first phase, Ni2Si, is parabolic with time, whilst the second, NiSi, grows linearly with time. The simultaneous presence of both diffusion and reaction-rate-limiting mechanisms is implied by the parabolic and linear growth laws. An investigation of the electrical characteristics of diodes which were metallized and heat-treated simultaneously shows little change in the barrier height.
81 citations
14 Jun 1976
TL;DR: The rectenna which captures and rectifies the microwave power at the receiving end of a free space microwave power transmission system is comprised of many elements consisting of halfwave dipoles with microwave filter and rectification circuits attached.
Abstract: The rectenna which captures and rectifies the microwave power at the receiving end of a free space microwave power transmission system is comprised of many elements consisting of halfwave dipoles with microwave filter and rectification circuits attached. This element has been independently optimized for efficiency and analyzed for losses. The paper describes the device, the special test equipment used, the results of the mathematical modelling and computer simulation, special low loss Schottky barrier diodes that have been constructed to improve the efficiency, and life tests that have been made on these devices. An efficiency, defined as the ratio of DC power output to incident microwave power, of over 90% has been achieved.
69 citations
TL;DR: Capacitance-voltage characteristics have been obtained for Schottky barrier diodes, formed on polished surfaces of natural p-type semiconducting diamond, before and after illumination with radiation capable of neutralizing ionized donors in the depletion layer as mentioned in this paper.
Abstract: Capacitance-voltage characteristics have been obtained for Schottky barrier diodes, formed on polished surfaces of natural p-type semiconducting diamond, before and after illumination with radiation capable of neutralizing ionized donors in the depletion layer. Plots of 1/C2 versus V for the two cases have yielded values for both the acceptor concentration NA and the donor concentration ND. Comparison of these data with those obtained from Hall effect measurements indicate that the latter overestimate the value of NA-ND by almost a factor of 2. The boron concentration has been determined in approximately the same surface layer as the capacitance measurements by detecting the alpha -particles emitted during irradiation with 700 keV protons using the reaction 11B(p, alpha 1)8Be* to 2 alpha 2. A quantitative correlation has been obtained between the boron and acceptor concentrations.
TL;DR: In this article, the electrical characteristics and interdiffusion in n -GaAs Schottky diodes containing Ti and Pt/Ti have been studied using I-V, C-V and X-ray diffraction and Rutherford backscattering measurements.
Abstract: The electrical characteristics and interdiffusion in n -GaAs Schottky diodes containing Ti and Pt/Ti have been studied using I-V, C-V, X-ray diffraction and Rutherford backscattering measurements. Thermal aging of the diodes was carried out in vacuo at 350 and 500°C. The Ti/ n -GaAs diodes show near-ideal forward I-V characteristics with the ideality parameter n ⋍ 1·03 and the barrier height φ B ∼ 0·84 V . C-V data yield the same φ B . No interdiffusion was observed at 350°C. At 500°C, TiAs forms but the φ B remains unchanged. Pt/Ti/ n -GaAs diodes behave “Pt-like” upon aging at 500°C with φ B ∼ 0·9 V and n ∼ 1·1. The TiAs formed at 500°C is ineffective in preventing a subsequent Pt/GaAs interaction which leads to a layered arrangement of reaction products consisting of Pt 3 Ga/TiAs/PtAs 2 / n -GaAs.
Patent•
20 Sep 1976TL;DR: In this article, a semiconductor read-only-memory (ROM) unit is fabricated in large-scale-integrated form utilizing the formation of self-isolating bit-line surface regions of one conductivity type directly in a bulk region of the opposite conductivities type.
Abstract: A semiconductor read-only-memory (ROM) unit fabricated in large-scale-integrated form utilizing the formation of self-isolating bit-line surface regions of one conductivity type directly in a bulk region of the opposite conductivity type. Channel-stop regions of the same conductivity type as the bulk region are formed in the spaces between bit-line regions. Metallic word-lines overlying and orthogonal to the bit-line regions are formed, separated from the bit-line regions by an insulating layer. The memory cell comprises a single Schottky diode. Such a diode is made or not at each word-line/bit-line crossover location depending respectively on whether or not an aperture is formed in the insulating layer during fabrication to permit the word-line to contact a lightly doped portion of the bit-line. ROM units formed by this method are characterized by small area, high speed, low power dissipation and low cost.
TL;DR: In this article, the Schottky barrier for holes on common III-V and II-VI semiconductors contacted by Au is shown to depend only on the anion.
Abstract: The Schottky barrier for holes on common III–V and II–VI semiconductors contacted by Au is shown to depend only on the anion. Compilation of the experimental data shows that compound semiconductors with the same anion but different cations possess very similar values for the the Au Schottky barrier for holes. Further, the data show that the Pauling electronegativity of the anion provides a useful ordering parameter for the height of the Schottky barrier. This correlation is compared with analogous barrier data on rocksalt and layer structures as well as earlier results for the semiconductor–vacuum interface.
TL;DR: In this paper, the thermal reaction of a vacuum-evaporated Ti film with substrate GaAs has been investigated using Auger electron spectroscopy and x-ray diffractometry.
Abstract: The thermal reaction of a vacuum‐evaporated Ti film with substrate GaAs has been investigated using Auger electron spectroscopy and x‐ray diffractometry. As accumulation and Ga depletion at the Ti/GaAs interface and Ga pileup in front of the As‐rich layer have been observed. The As‐rich and the Ga‐rich layers have been found to be composed of TiAs/Ti5As3 and Ti2Ga3/Ti5Ga4, respectively. It has also been found that the rate of the Ti‐GaAs reaction is governed by the interdiffusion process of Ti and As at the interface with an activation energy of 1.70±0.05 eV. The low diffusivity and relatively high Schottky barrier height of the present system facilitate the formation of useful Schottky barrier junctions.
TL;DR: In this paper, the authors evaluated the performance of Schottky-barrier diodes operating in the thermionic mode by applying the laws of vacuum tube electronics to the space charge region and by incorporating the treatment of the series-resistance effect into the discussion.
Abstract: Transit‐time and series‐resistance effects in heavily doped Schottky‐barrier diodes operating in the thermionic mode are evaluated by applying the laws of vacuum tube electronics to the space‐charge region and by incorporating the treatment of the series‐resistance effect into the discussion. It is assumed that the field distribution in the space‐charge region is linear, that collisions in the space‐charge region can be neglected, and that the signals are so small thatr the equations of motion can be linearized. The case of uniform field distribution is also briefly dealt with; the results are not significantly different from the linear field case. At a frequency equal to three times the plasma frequency of the bulk semiconductor the detection and mixing efficiency is about 0.25 times the low‐frequency value. The effect of the high‐frequency conductance of the space‐charge region turns out to be quite small when the series‐resistance effect is taken into account; the performance is then determined by a single transit‐time factor ‖g (jω) ‖2 and a series‐resistance factor that is independent of transit time. The effect of tunneling on the device performance is discussed briefly. Satisfactory detection and mixing performance seems feasible for the 10–40‐μm wavelength range.
TL;DR: In this article, a new nuclear Betavotaic battety is described, which uses a Schottky barrier in place of the more standard p-n junction diode, along with 147Pm metal film rather than Pm2O3 oxide as in the commercially available Betacel.
Abstract: A new nuclear betavotaic battety is described. It uses a Schottky barrier in place of the more standard p-n junction diode, along with 147Pm metal film rather than Pm2O3 oxide as in the commercially available Betacel. Design details of the battery including measurement of absorption, conversion efficiency, thickness etc. as functions of & resistivity and other cell parameters are described. A prototype design is discussed and its performance assessed.
Patent•
14 May 1976
TL;DR: An improved method of fabricating metal-semiconductor interfaces such as Schottky barriers and ohmic contacts is described in this article. But this method is not suitable for the manufacturing of transistors and other electronic components.
Abstract: An improved method of fabricating metal-semiconductor interfaces such as Schottky barriers and ohmic contacts. There is disclosed apparatus and method (or process) for chemically converting, etching, or passivating the surface of a material, such as the surface of a silicon wafer, in a gaseous plasma environment consisting of atomic, neutral nitrogen which causes the surface of the material to be resistant to otherwise subsequent nascent surface oxide buildup. This process is particularly useful in manufacture of Schottky diodes, transistors, and other electronic components or discrete and integrated devices requiring high quality metal-semiconductor junctions or interfaces.
TL;DR: In this article, a method for capless annealing of ion-implanted GaAs, which gives electrical activation of Seimplanted wafers nearly identical to that obtained with sputtered silicon nitride caps, is described.
Abstract: A method is reported for capless annealing of ion‐implanted GaAs which gives electrical activation of Se‐implanted wafers nearly identical to that obtained with sputtered silicon nitride caps. State‐of‐the‐art performance has been realized from Schottky‐gate FET’s fabricated from this material.
TL;DR: In this paper, the existence of a thin layer between the metal and semiconductor which has a high charge density, high trap density, and is conducting observed barrier height changes are explained by the trapping of charge carriers flowing through the layer and the lowered avalanche breakdown voltage by heating of the high field in the intervening layer.
Abstract: Two frequently observed problems with Schottky diodes are soft current–voltage characteristics and low avalanche breakdown voltages These problems are sometimes found immediately upon fabrication, or they may develop during use It is proposed that these phenomena can be explained by the existence of a thin layer (25–250 A thick) between the metal and semiconductor which (i) has a high charge density, (ii) has a high trap density, and (iii) is conducting Observed barrier height changes are explained by the trapping of charge carriers flowing through the layer and the lowered avalanche breakdown voltage by heating of carriers in the high field in the intervening layer These explanations have been confirmed by measurements on GaP and GaAs diodes having a deliberately grown thin interfacial oxide ∠100 A thick Such an interfacial layer can be detected using a pulsed current–voltage technique described in the paper
TL;DR: A dc-to-rf conversion efficiency of 37% combined with an output power of 3.4 W at 3.3 GHz has been obtained from a Schottky-barrier GaAs IMPATT diode having a lo-hi-lo profile.
Abstract: A dc‐to‐rf conversion efficiency of 37% combined with an output power of 3.4 W at 3.3 GHz has been obtained from a Schottky‐barrier GaAs IMPATT diode having a lo‐hi‐lo profile. The donor spike or clump was produced by implanting silicon into an epitaxial layer with a n‐type concentration of 1.65×1015 cm−3. Pyrolytic Si3N4 was used to encapsulate the GaAs during the postimplantation anneal. For these devices, the Si3N4 deposition procedure was found to be critical and had to be optimizied to achieve reproducible results. The devices have had very uniform electrical characteristics, and a large yield of devices with greater than 30% efficiency has been obtained. These results indicate that implantation can be used to produce lo‐hi‐lo IMPATT’s with significantly higher device yields than have been obtained by epitaxial techniques.
TL;DR: In this article, a review of nonlinear devices that have been used or are potentially useful for laser frequency measurement in the optical region, extending from the submillimetre to the ultraviolet.
Abstract: Reviews nonlinear devices that have been used or are potentially useful for laser frequency measurement in the optical region, extending from the submillimetre to the ultraviolet. The devices are grouped mainly in two classes: point-contact junctions and bulk nonlinear crystals or gases. Their physical principles and limitations are discussed, and attainments when constructed of various materials are listed. Ways of measuring frequencies with them are considered.
TL;DR: In this article, a general model for the analysis of metal-semiconductor solar cells is presented, which takes into account the cell optical properties, carrier recombination effects, semiconductor minority carrier properties, series resistance, cell thickness, and active surface area.
Abstract: A general model for the analysis of metal‐semiconductor solar cells is presented. The model takes into account the cell optical properties, carrier recombination effects, semiconductor minority‐carrier properties, series resistance, cell thickness, and active surface area. Numerical methods are used to solve the appropriate continuity equations and hence compute the photocurrent density under AMO conditions. The operation of the model is demonstrated using p‐ and n‐type Si and GaAs with Au being taken as the barrier metal. Calculations are presented showing the effect on solar energy conversion efficiency of surface recombination velocity, barrier height, minority‐carrier lifetime, barrier metal thickness, collecting grid configuration, and cell thickness. A comparison of practical and computed data for the Au/n‐GaAs system yields good agreement.
TL;DR: In this article, the spectral response of Schottkyd diodes at short wavelengths was analyzed for photovoltaic solar cells and it was shown that a reasonable percentage of the available carriers can be collected even when the diffusion lengths are much smaller than this.
Abstract: The collection efficiency for carriers optically generated in the depletion region of photovoltaic solar cells is analyzed. For p‐n junction devices, it is shown that virtually all these carriers are collected provided the minority carrier diffusion lengths are larger than the width of the depletion layer, and that a reasonable percentage will be collected even when the diffusion lengths are much smaller than this. For Schottky diode devices, the collection efficiency for carriers optically generated near the metal‐semiconductor interface is shown to be small and to depend critically upon the exact model of the contact used. As a consequence the spectral response of Schottky diodes at short wavelengths is shown to contain considerable information regarding the physics of the metal‐semiconductor contact. New surface insulator devices are shown to have a short‐wavelength response superior to that of Schottky diodes.
TL;DR: In this paper, the series resistances of some devices can be reduced significantly, thus effecting increases in the cutoff frequencies, and the resistance swing of Schottky diodes can also be raised.
Abstract: The fabrication of ultra-thin silicon membranes of micron or submicron sizes with thicker supporting frames makes possible improvements in several kinds of electronic devices. We show that the series resistances of some devices can be reduced significantly, thus effecting increases in the cutoff frequencies. The resistance swing of Schottky diodes can also be raised. Initial experimentation relating to some of these applications is presented.
TL;DR: In this article, the authors proposed an explanation for the operation of such solar cells based on the concept that they are minority-carrier nonequilibrium MIS tunnel diodes, which can increase the photovolatic conversion efficiency of such devices.
Abstract: Recent reports in the literature indicate that the introduction of an interfacial oxide layer in a Schottky barrier can increase greatly the photovolatic conversion efficiency of such devices. We propose an explanation for the operation of such solar cells based on the concept that they are minority‐carrier nonequilibrium MIS tunnel diodes.
TL;DR: In this article, the Schottky field assisted thermionic emission is the dominant conduction mechanism in the temperature range 390 to 440 K and the metalinsulator work function is calculated to ≈ 1.83 eV.
Abstract: The electrical conduction in Ag-polypropylene-Ag sandwich samples is studied measuring the dependence of current (I) on voltage (U) and temperature (T). The experimental results of I–U–T relationships show that Schottky field assisted thermionic emission is the dominant conduction mechanism in the temperature range 390 to 440 K. The metalinsulator work function is calculated to ≈ 1.83 eV. Hysteresis and polarization effects are also observed in the I–U characteristics in this range of temperature. Contribution due to bulk polarization is suggested in the conduction mechanism besides the Schottky emission.
01 May 1976
TL;DR: In this paper, a novel acoustoelectric device capable of storing large bandwidth analog signals and correlating the stored signal with other signals is described, which uses charge storage in an array of Schottky diodes on a silicon strip mounted adjacent to a lithium niobate surface-wave delay line.
Abstract: A novel acoustoelectric device capable of storing large bandwidth analog signals and correlating the stored signal with other signals is described. The device uses charge storage in an array of Schottky diodes on a silicon strip mounted adjacent to a lithium niobate surface-wave delay line. The paper emphasizes experimental results characterizing the device in terms of storage capacity, storage time, linearity, and efficiency. Based on the experimental data, a short discussion is given on anticipated performance limitations.
TL;DR: In this article, the theoretical and experimental results of a FET mixer with an IF preamplifier are described, and the experimental conversion gain is 6 dB at the RF frequency of 10.8 GHz and the IF frequency of 1.7 GHz.
Abstract: GaAs metal-semiconductor FET's (MESFET) are developed for use in amplifiers at microwave frequencies. The FET has a Schottky barrier between the gate and source, operating in the same manner as a Schottky-barrier diode. If the Schottky barrier is used as a mixer, the IF signal is generated and simultaneously amplified by the FET itself. Thus a mixer with IF preamplifier can be realized. In this paper the theoretical and experimental results of a FET mixer are described. In such operations, the conversion loss in the freqnency conversion alone is large due to the high series resistance of the Schottky barrier. However, the overall FET mixer has a "conversion gain" because the IF gain of the FET is made large. The experimental conversion gain is 6 dB at the RF frequency of 10.8 GHz and the IF frequency of 1.7 GHz. The noise figure of the FET mixer is at present large (15 dB, for example), due to large conversion loss in the frequency conversion.
TL;DR: In this article, a contact array diode was proposed for Schottky-barrier detection with diameters as small as 1000 /spl Aring/ have been achieved using 0.5-mu m-diam diodes.
Abstract: Schottky-barrier diode detection has been extended to 7.2 THz (42 mu m) using 0.5-mu m-diam diodes. The diodes were fabricated on bulk-doped n-type GaAs using electron lithographic techniques; diameters as small as 1000 /spl Aring/ have been achieved. A new approach in Schottky-barrier design, the contact array diode, is proposed. The diode is fabricated from readily available bulk doped material, and a performance is indicated that is competitive to the conventional epitaxial Schottky-barrier mixer well into the submillimeter wavelength region. A scanning electron microscope (SEM) photograph of diode array structures is shown.