共查询到20条相似文献,搜索用时 15 毫秒
1.
K. A. Jones R. T. Lareau T. Monahan J. R. Flemish R. L. Pfeffer R. E. Sherriff C. W. Litton R. L. Jones C. E. Stutz D. C. Look 《Journal of Electronic Materials》1995,24(11):1641-1648
Symmetric δ-doped InGaP and AlGaAs PHEMT structures have been grown by organometallic vapor phase epitaxy with properties
that approach those of MBE grown AlGaAs structures. The 300 and 77K carrier concentrations for the InGaP PHEMT were 2.72 and
2.56 × 1012 cm2
−2 and the mobilities were 5,920 and 22,000 cm2
2/V.s. These excellent values suggest that problems associated with switching the anion at the channel heterojunction have
been overcome. The corresponding values for the AlGaAs PHEMT were 2.51 and 2.19 × 1012 cm2
−2 and 6,500 and 20,400 cm2/V.s. The uniformity in the indium concentration in the InGaAs layer as determined by photoluminescence, photoreflection,
double crystal x-ray diffraction, and Rutherford backscattering was found to be good, but the percent In in the AlGaAs pseudo-morphic
high electron mobility transistor (PHEMT) was less than that in the InGaP PHEMT even though the programmed values were the
same. The uniformity in the doping distribution as determined by secondary ion mass spectroscopy and electrochemical capacitance-voltage
measurements was found to be good, but it decreased with distance from the center of the susceptor. Also, most of the dopants
in the δ-doped InGaP and AlGaAs layers were activated. 相似文献
2.
Kinoshita H. Ishida T. Akiyama M. Inomata H. Sano Y. Nishi S. Kaminishi K. 《Electronics letters》1985,21(23):1062-1064
Inverted-structure high electron mobility transistors with insulated-gate structure, i.e. AlGaAs/GaAs/n-AlGaAs, have been successfully applied to E/D-type DCFL ring oscillators. High transconductance of 280 mS/mm was obtained at 77 K in an enhancement-mode FET with 0.8 ?m gate length. Gate leakage current was small enough even at a gate voltage of +1.4 V both at 300 K and 77 K, and a high logic swing of more than 1 V was achieved using a DCFL inverter. A 21-stage ring oscillator showed a minimum gate delay as small as 18.0 ps with power dissipation of 520 ?W/gate at 77 K. 相似文献
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Nishi S. Seki S. Saito T. Fujishiro H.I. Sano Y. 《Electron Devices, IEEE Transactions on》1989,36(10):2191-2195
A gate recess process for a 0.5-μm I-HEMT (inverted high electron mobility transistor) has been developed. A drain conductance for the 0.5-μm I-HEMT as small as 2 mS/mm was achieved, indicating a small short-channel effect. The threshold voltage uniformities were studied in microscopic and macroscopic areas in a 2-in wafer. The uniformities are very high, i.e. the standard deviations of microscopic and macroscopic areas are 10 and 30 mV, respectively, at a threshold voltage of 0.1 V. An 8×4 parallel multiplier was fabricated, and a multiplication time of 1.67 ns was obtained at room temperature. An 8-b digital/analog converter (DAC) was fabricated and operated at a clock rate of 1.2 GHz. The DC linearity of the DAC is better than 0.18 LSB. These results confirm that an I-HEMT is very well suited for high-speed integrated circuits 相似文献
5.
Kuroda S. Harada N. Katakami T. Mimura T. Abe M. 《Electron Devices, IEEE Transactions on》1989,36(10):2196-2203
The authors studied the nonalloyed ohmic characteristics of HEMTs (high electron mobility transistors). At high integration levels, nonalloyed ohmic contacts were found to have two advantages: an extremely short ohmic length with low parasitic source series resistance and direct connection between the source/drain and gate with the same metal. The propagation delay in a ring oscillator with a single-metal source/drain and gate formed simultaneously was 37 ps/gate (L g=0.9 μm). The very short ohmic metal contacts and just three contact holes made it possible to reduce the memory cell area greatly. The cell is 21.5×21.5 μm2, one of the smallest ever reported for a GaAs-based static RAM. Using smaller load HEMTs or resistor loads in the memory cell, combined with nonalloyed ohmic technology with quarter- or subquarter-micrometer-gate HEMTs it is possible to fabricate a very-high-speed LSI such as a 64-kb static RAM with a reasonable chip size 相似文献
6.
Bushehri E. Thiede A. Staroselsky V. Timochenkov V. Lienhart H. Bratov V. Jakobus T. 《Electronics letters》1998,34(10):934-936
A T&H circuit with a sampling rate of 6 Gsample/s has been experimentally demonstrated in AlGaAs/GaAs/AlGaAs HEMT technology. The circuit utilises a dual bridge topology suitable for interleaved ADC circuits, doubling the effective sampling rate with an insignificant increase in area compared to the previously reported solutions 相似文献
7.
P. N. Brunkov A. A. Gutkin M. E. Rudinsky O. I. Ronghin A. A. Sitnikova A. A. Shakhmin B. Ya. Ber D. Yu. Kazantsev A. Yu. Egorov V. E. Zemlyakov S. G. Konnikov 《Semiconductors》2011,45(6):811-817
The depth distribution of free carriers over the HEMT structures with quantum-well layers is studied by electrochemical capacitance-voltage profiling. It is shown that the actual distribution of the concentration of free carriers and their energy spectrum in the HEMT structure channel can be obtained by numerical simulation of the results of profiling based on the self-consistent solution of one-dimensional Schrödinger and Poisson equations. 相似文献
8.
《Electron Device Letters, IEEE》1983,4(2):42-44
The substantial reduction in gate metallization resistance and improvement in performance of submicron-gate GaAs FET's has been achieved by employing a mushroom profile defined by electron-beam exposure. Using MBE growth of buffer, channel, and n+ contact layers, minimum noise figures of 1.0-1.1 dB have been demonstrated at 8 GHz, with associated gains of 13-14 dB. 相似文献
9.
A procedure for the inverse modeling of GaAs/AlGaAs HEMT structures from the DC I -V characteristic is described. The procedure allows important structural parameters, including the aluminum fraction, dopant density, doped layer thickness, spacer layer thickness, physical gate length, source resistance, drain resistance, and the saturated electron velocity, in the 2DEG and in the doped AlGaAs to be obtained. The accuracy of the inverse modeling procedure is established by comparison of the derived HEMT structure with experimental results 相似文献
10.
Ultra-submicrometer-gate AlGaAs/GaAs high-electron-mobility transistors (HEMTs) that have gate lengths ranging from 25 to 85 nm and were fabricated using electron-beam lithographic techniques on epitaxial wafers grown by molecular beam epitaxy are discussed. These devices show that velocity overshoot and short-gate geometry effects play an important role for the gate lengths less than 100 nm. The maximum intrinsic transconductance is 215 mS/mm, and the effective saturated electron velocity reaches 3×107 cm/s for a 30-nm HEMT 相似文献
11.
本文介绍了用分子束外延法制作的梯度折射率分别限制式单量子阱GaAs/AlGaAs半导体激光器。该器件具有较低的阈值电流密度和单模运转特性,连续输出功率可达55mw。 相似文献
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A practical method to evaluate the parasitic source resistance R/sub s/ and drain resistance R/sub d/ of high electron mobility transistors (HEMTs) is presented. DC results for R/sub s/ and R/sub d/ can be used as initial values in the determination of linear and nonlinear equivalent circuits by optimisation.<> 相似文献
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High-temperature devices are required for a large number of industrial applications. In order to demonstrate the feasibility of a high temperature operating circuit on GaAs an operational amplifier was designed and fabricated. A corresponding technology for transistors and circuits for operation up to 300°C with AlGaAs/GaAs/AlGaAs DHBT's is presented. For the amplifier circuit an open loop gain of 49.5 dB at room temperature and 35.8 dB at 200°C was measured, which is in good agreement with the circuit simulation. High temperature stability has been proven by a storage test at 400°C over 1000 h for the ohmic contact metallization and 200 h for the transistors 相似文献
16.
《Electron Devices, IEEE Transactions on》1986,33(11):1626-1634
Although MODFET's have exhibited the fastest switching speed for any digital circuit technology, there is as yet no clear consensus on optimal inverter design rules. We therefore have developed a comprehensive MODFET device model that accurately accounts for such high gate bias effects as transconductance degradation and increased gate capacitance. The device model, which agrees with experimental devices fabricated in this laboratory, is used in the simulation of direct-coupled FET logic (DCFL) inverters with saturated resistor loads. Based on simulation results, the importance of large driver threshold voltage not only for small propagation delay times but for wide logic swings and noise margins is demonstrated. Furthermore, minimum delay times are found to occur at small supply voltages as seen experimentally. Both of these results are attributed to the reduction of detrimental high gate bias effects. The major effect of reducing the gate length on delay time is to decrease the load capacitance of the gate. Using 0.25-µm gates, delay times of 5 and 3.6 ps at 300 and 77 K, respectively, are predicted. Finally, the recently introduced In-GaAs/AlGaAs MODFET's are shown to have switching speeds superior to those of conventional GaAs/AlGaAs MODFET's. 相似文献
17.
分析了AlGaAs/GaAs/AlGaAs渐变异质结的光致发光特性。根据理论及仿真结果,确定了GaAs发光的最优能带结构为双异质结P-AlGaAs/P-GaAs/P-AlGaAs或者N-AlGaAs/N-GaAs/ N-AlGaAs,并且异质结两边能带渐变。基于所选结构,研究了能带渐变及层宽对发光效率的影响。研究结果表明,外体区吸收层的能带渐变,且外体区激发层的能带不变,发光区域的载流子最多,发光能量值最大。激励光源的波长不同,各层有不同的最优宽度,为器件的整体优化提供了依据。AlGaAs/GaAs/AlGaAs渐变异质结的光致发光研究为高效率器件如太阳电池、发光二极管等的实用化设计、研制提供了有价值的参考。 相似文献
18.
An oscillatory dependence of the electron mobility on the quantum well (QW) thickness in a AlGaAs/GaAs/AlGaAs heterostructure with double-sided modulation doping has been observed experimentally. A steep decrease in mobility with increasing electron concentration in the QW is established. The conditions for an increase in mobility on introducing a thin barrier into the QW are determined. The first experimental observation of an increase in mobility by a factor of 1.3 in a QW of thickness L=26 nm upon introducing a thin (1–1.5 nm) AlAs barrier is reported. 相似文献
19.
Maykel Courel Julio C. Rimada Luis Hernndez 《Progress in Photovoltaics: Research and Applications》2013,21(3):276-282
A theoretical model is performed to study the viability of the AlGaAs/GaAs superlattice solar cell (SLSC). Using the Transfer Matrix Method, the conditions for resonant tunneling are established for a particular SL geometry with variably spaced quantum wells. The effective density of states and the absorption coefficient are calculated to determinate the J–V characteristic. Radiative, non‐radiative, and interface recombination were evaluated from a modeled SLSC, and their values were compared with a multiple quantum well solar cell of the same aluminum composition. A discussion about the conditions, where SLSC performance overcomes that of a multiple quantum well solar cell, is addressed. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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