Showing papers on "Induced high electron mobility transistor published in 1985"
TL;DR: In this article, a Schottky-gate FET with a 2D electron gas was presented, which was scaled down to its ultimate physical limit normal to the crystal surface.
Abstract: A new Schottky-gate FET grown by molecular-beam epitaxy is presented. A V-shaped potential well with a 2D electron-gas is generated in the epi-layer by implementation of a δ-function like doping profile. The δ-doped FET is scaled down to its ultimate physical limit normal to the crystal surface. The advantages of the new device are high gate-breakdown voltage, high transconductance due to the proximity of the electron channel to the crystal surface, and high electron concentration in the channel. Current-voltage and capacitance-voltage measurements reveal a large breakdown voltage and a narrow impurity and carrier distribution.
104 citations
82 citations
TL;DR: In this article, the authors reported a degradation in effective channel mobility with increasing degree of nitridation, as much as 50% for electrons, noticeably less for holes while both hole and electron mobilities are degraded by Coulombic scattering from nitrification-induced fixed charge.
Abstract: Reports a degradation in effective channel mobility with increasing degree of nitridation, as much as 50% for electrons, noticeably less for holes While both hole and electron mobilities are degraded by Coulombic scattering from nitridation-induced fixed charge, the additional mobility degradation for electrons is attributed to a reduction of the mobile electron density by electron trapping in near-interface traps and to additional Coulombic scattering of the remaining channel electrons by the trapped electrons >
82 citations
TL;DR: In this paper, experimental results of surface mobility (effective mobility) in n-channel metal-oxide-semiconductor field effect transistors subjected to high electric field stress are presented, and the electron mobility limited by Coulomb scattering is extracted from the experimental data comparing the measured effective mobility before and after the stress.
Abstract: Experimental results of surface mobility (effective mobility) in n‐channel metal‐oxide‐semiconductor field‐effect transistors subjected to high electric field stress are presented. The electron mobility limited by Coulomb scattering is extracted from the experimental data comparing the measured effective mobility before and after the stress. The low‐temperature data (T=77 K) are discussed in terms of the Stern–Howard two‐dimensional Coulomb scattering theory in the electric quantum limit approximation.
25 citations
TL;DR: In this paper, a simple but general model for explaining the series resistance dependence of transconductance and field effect mobility is developed, which enables a quantitative analysis of series resistance effects on the maximum mobility and the corresponding gate voltage, has been successfully tested on short channel MOSFETs with various channel lengths and external series resistances.
Abstract: A simple but general model for explaining the series resistance dependence of transconductance and field-effect mobility is developed in the letter. This model, which enables a quantitative analysis of series resistance effects on the maximum mobility and the corresponding gate voltage, has been successfully tested on short-channel MOSFETs with various channel lengths and external series resistances.
15 citations
10 citations
TL;DR: In this paper, a planar-type amorphous-silicon metal-oxide-semiconductor transistors have been proposed and their features have been demonstrated, including the gate insulator of silicon-dioxide grown inside the original AMO layer, which makes transistor characteristics highly stable.
Abstract: Novel planar-type amorphous-silicon metal-oxide-semiconductor transistors have been proposed and their features have been demonstrated. The gate insulator of silicon-dioxide grown inside the original amorphous-silicon layer makes transistor characteristics highly stable. The source and drain of micro-crystal silicon make the fabrication process simple and the parasitic elements small. The on-current of the prototype transistor was extrapolated to decrease to one-half of its initial value 1010 years after the application of dc bias. The on-off current ratio was about 106 and no voltage offset was observed. The field-effect mobility was 0.6 cm2/Vs.
9 citations
TL;DR: In this article, the authors show that the data can be understood without modification of the existing theory, and reiterate that the observed drift mobility and density of localized states require an extended-state electron mobility in excess of 100 cm2/V-s.
9 citations
Patent•
08 Mar 1985
TL;DR: In this article, the authors proposed a multilayered structure for high electron mobility semi-conductor devices, where the second spacer is inserted between the spacer (first spacer) and the doped layer to prevent the diffusion of impurity.
Abstract: In order to make an IC comprising a high electron mobility semi-conductor device, it is necessary to ensure that the carrier in the channel layer does not lose its high mobility by virtue of thermal treatment in the IC fabrication process. It has been found that the mobility of two dimensional electron gas (2DEG) is lost by scattering of ionized impurity diffused from the doped layer into the spacer layer which separates the 2DEG in the channel layer from the doped layer. According to the invention, another spacer (second spacer) is inserted between the spacer (first spacer) and the doped layer to prevent the diffusion of impurity. The proposed multilayered structure is as follows. A channel layer made of i-GaAs is formed on a high resistivity GaAs substrate. A first spacer layer of undoped AlxGal-xAs is formed over the channel layer and the second spacer layer of i-GaAs is formed over the first spacer layer. A doped layer of n-Al Gal As is then formed over the second spacer layer. The thickness of the second spacer layer is approximately 20 .ANG., and that of the first spacer is approximately 40 .ANG.. Applying such structure to the high electron mobility transistor, it can withstand the heat treatment of 750°C for 10 min. and annealing at more than 950°C for 10 sec. without loss of mobility.
6 citations
TL;DR: In this paper, a 3-in.substrate MBE system with a cell-substrate distance of 25 cm was developed, and sufficiently high uniformity (± 1% variation in the layer thickness, doping concentration, and AlAs mole fraction of Si−doped AlGaAs over a 56mm-diam area) as well as high quality of a GaAs/N-AlGaAs heterostructure (electron mobility of 1.96×105 cm2/V at 77 K) for high electron mobility transistor IC application was achieved with the new MB
Abstract: Extremely high electron mobilities of 2.4×106 cm2/V s (4.2 K) and 2.05×105 cm2/V s (77 K) with a sheet electron concentration of about 5.3×1011 cm−2 were achieved in a selectively doped GaAs/N–AlGaAs heterostructure with a GaAs–AlGaAs heterostructure buffer layer grown by MBE. A new 3‐in.‐substrate MBE system having a cell‐substrate distance of 25 cm was developed, and sufficiently high uniformity (±1% variation in the layer thickness, doping concentration, and AlAs mole fraction of Si‐doped AlGaAs over a 56‐mm‐diam area) as well as high quality of a GaAs/N–AlGaAs heterostructure (electron mobility of 1.96×105 cm2/V s at 77 K) for high electron mobility transistor IC application was achieved with the new MBE system.
5 citations
01 Feb 1985
TL;DR: In this article, it was shown that blocking of minority carrier injection in the emitter, and hence a large increase of the current gain, can be achieved with a new type of npn bipolar transistor, where emitter is made of n-doped hydrogenated amorphous silicon (a-Si: H).
Abstract: The limitation of the maximum current gain attainable in a silicon bipolar transistor is due to many factors whose main effect is to prevent the blocking of minority carrier injection in the emitter. In the paper we show that blocking of minority carrier injection in the emitter, and hence a large increase of the current gain, can be achieved with a new type of npn bipolar transistor, where the emitter is made of n-doped hydrogenated amorphous silicon (a-Si: H). It is demonstrated that the very low mobility of carriers and the large bandgap (around 1.8 eV) in amorphous silicon are the two main factors involved in the improvement of the gain. The feasability and the potential interest of the device are studied in detail on the basis of the up-to-date known electrical properties of doped a-Si: H.
TL;DR: In this paper, the effect of thermally generated acoustic layer modes in the silicon dioxide gate of a silicon MOSFET on inversion layer electron mobility was investigated using the deformation potential formalism.
TL;DR: In this paper, a hole injection electrode between Ni/Au-Ge ohmic contacts to the het-erostructure of a 21XEG heterostrucure was proposed.
Abstract: their high-current drivability. However, their structure is so tom-plicated that it is difficult to fabricate fine devices and high-deltsity IC's. This paper reports a new high-speed device utilizing a 21XEG heterostrucure, which has high-current drivability as well as a ;im-ple device structure. The new device has an n-AIGaAs/GaAs selectively doped het-erostructure with a pf GaAs (NA = 3 X lOI9 ~ m-~) hole injection electrode between a couple of Ni/Au-Ge ohmic contacts to the het-erostructure. This structure is fully planar and similar to that D f a pf gate selectively doped saructure FET [ 11. However, the n. Al-GaAs layer is so thin (300 A , No = 2 X 10 \" cmF3) that there are scarcely any electrons in the entire region of the heterostructur : in thermal equilibrium. When a lot of holes were injected to this .1(4t-erostructure, a high-current mode operation was achieved. A device with a 0.5 p m X 100 pm pf hole injection electrode exhib.ted extremely high transconductance of 3000 mS/mm for FET mxle operation at 300 K. Current gains for bipolar transistor mode operation (6) were 25 in the low-current level and 6-8 in the hlgh-current level. The maximum current exceeded 1 A/mm, which is about two times larger than that for GaAs MESFET's and 4 times larger than that for selectively doped structure FET's. This operation mode is considered as follows. Injected holes \\fill induce the same amount of electrons in the heterostructure, es?e-cially in GaAs side due to the conduction band discontinuity. Th :se electrons flow along the herterointerface, like 2DEG between a couple of ohmic contacts. The current gain is possibly proportional to the ratio of a high saturation velocity of electrons to a low d:ift velocity of holes. Therefore, the AlGaAsIGaAs heterostrucure is advantageous in regard to current gain over a lateral GaAs transistor reported recently, which is also operated by hole injection [ 21. The new device has further advantages of simpler device structu :e, simpler fabrication process, and possibly lower parastic capacitar ce due to the depleted n-AlGaAs layer. High-frequency and high-speed performances will be presented. Modulation-doped semiconductor heterojunctions have led to a variety of high-mobility two-dimensional electron gas transistors with improved performance over conventional MOSFET's and MESFET's. To date, the best material and device results come from heterojunctions between n-doped GaAlAs and undoped GaA,s. However, these structures exhibit undesirable persistent photoco 1-ductivity attributed to deep levels …
TL;DR: In this paper, a two-dimensional numerical model has been developed for the analysis of operation of a high electron mobility transistor (HEMT) based on the AlGaAs/GaAs heterojunction.
Abstract: A two-dimensional numerical model has been developed for the analysis of operation of a high electron mobility transistor (HEMT) based on the AlGaAs/GaAs heterojunction. In this model, the basic equations are formulated under the assumption that the band structure is continuous and Boltzmann statistics are applicable. Further, it is assumed that the velocity-electric field curve of the two-dimensional electron gas system is identical to that of the bulk GaAs. The calculations have been performed for the device with a 1 μm gate length and the following results have been made on the operating mechanism of the HEMT. 1 In the short-channel HEMT, the electron velocity saturates in the channel directly below the drain-side edge of the gate electrode and as a result the current also saturates. 2 In the HEMT operated in the saturation region, an electron accumulation region is formed in the GaAs layer below the drain-side edge of the gate electrode. In this region, the current flow significantly extends into the bulk GaAs from the heterojunction interface. 3' A strong electric field concentration occurs in this region and the major portion of the applied drain voltage is sustained by this region. This concentration is limited in an extremely narrow region.