Gate current in AlInAs/GaInAs heterostructure insulated-gatefield-effect transistors (HIGFETs)

A self-aligned WSi gate heterostructure insulated-gate field-effect transistor (HIGFET) with a gate length of 1 μm was fabricated using an AlInAs/GaInAs heterostructure grown by atmospheric pressure metal-organic chemical vapor deposition (MOCVD). The gate current is investigated experimentally and theoretically. The measured gate current was found to be about two orders of magnitude higher than predicted by theory. The origin of this increase is unclear. However, the theoretical result suggests the possibility of reducing the gate current in AlInAs/GaInAs HIGFETs     

Performance of interface engineeredSiNx/ICL/InP/In0.53Ga0.47As/InP dopedchannel HIGFET's

SiN_x/InP/InGaAs doped channel passivated heterojunction insulated gate field effect transistors (HIGFETs) have been fabricated for the first time using an improved In-S interface control layer (ICL). The insulated gate HIGFETs exhibit very low gate leakage (10 nA@V_GS =±5 V) and I_DS (sat) of 250 mA/mm. The doped channel improves the DC characteristics and the HIGFETs show transconductance of 140-150 mS/mm (L_g=2 μm), f_t of 5-6 GHz (L_g=3 μm), and power gain of 14.2 dB at 3 GHz. The ICL HIGFET technology is promising for high frequency applications     

50-nm self-aligned-gate pseudomorphic AlInAs/GaInAs high electronmobility transistors

The design and fabrication of a class of 50-nm self-aligned-gate pseudomorphic AlInAs/GaInAs high electron mobility transistors (HEMTs) with potential for ultra-high-frequency and ultra-low-noise applications are reported. These devices exhibit an extrinsic transconductance of 1740 mS/mm and an extrinsic current-gain cutoff frequency of 340 GHz at room temperature. The small-signal characteristics of a pseudomorphic and a lattice-matched AlInAs/GaInAs HEMT with similar gate length (50 nm) and gate-to-channel separation (17.5 nm) are compared. The former demonstrates a 16% higher transconductance and a 15% higher current-gain cutoff frequency, but exhibits a 38% poorer output conductance. An analysis of the high-field transport properties of ultra-short gate-length AlInAs/GaInAs HEMTs shows that a reduction of gate length from 150 to 50 nm neither enhances nor reduces their average velocity. In contrast, the addition of indium from 53% to 80% improves this parameter by 19%     

Novel AlInAs/InP HEMT

The fabrication of the first AlInAs/InP HEMT is reported. This device has extrinsic transconductance of 40 mS/mm, gate-drain and drain-source breakdown voltages of 20 V and saturation drain current densities of 0.1 A/mm of gate width. These preliminary results show the potential of the AlInAs/InP heterojunctions for a wide variety of application including microwave power HEMTs.<>     

Kink-free AlInAs/GaInAs/InP HEMTs grown by molecular beam epitaxy

Kink-free AlInAs/GaInAs/InP HEMTs have been fabricated from an MBE structure grown under normal growth condition. Devices with 1 mu m gate-length exhibit an extrinsic transconductance of 450 mS/mm and a maximum drain current of 600 mA/mm which represent the best results for 1 mu m gate devices. The DC output conductance shows no kink over the entire gate bias range. The elimination of the kink is attributed to the high quality AlInAs buffer layer and a low mismatch between the AlInAs buffer layer and InP substrate.<>     

0.2 mu m gate length pseudomorphic HIGFET using novel selfaligned TiPtAu/WN T-gate technology for high-speed digital and millimetre wave applications

A selfaligned refractory gate HIGFET technology is described. A three-layer resist process has been used for gate TiPtAu thickening, making high-speed digital structures compatible with low noise microwave applications. Pseudomorphic HIGFETs with 0.2 mu m gate length exhibit a maximum transconductance of 600 mS/mm and a maximum oscillation frequency f/sub max/ of 100 GHz.<>     

High-performance Al/sub 0.48/In/sub 0.52/As/Ga/sub 0.47/In/sub 0.53/As MSM-HEMT receiver OEIC grown by MOCVD on patterned InP substrates

Reports the first demonstration of a new long-wavelength receiver OEIC comprising an AlInAs/GaInAs MSM detector and an AlInAs/GaInAs HEMT preamplifier. The layer structure was grown by LP-MOCVD on patterned InP substrates, which allowed independent optimisation of the MSM detector and HEMT preamplifier. The MSM detector showed the lowest leakage current yet reported and the HEMT exhibited a transconductance of 260 mS/mm. An excellent receiver response to 1.7 Gbit/s NRZ signals has been obtained.<>     

Highly stable microwave performance of InP/InGaAs HIGFETs

The fabrication and microwave performance of InP/InGaAs heterojunction insulated-gate FETs (HIGFETs) using plasma-enhanced chemical vapor deposition (PECVD)-deposited SiO₂ as the gate insulator are discussed. Extrinsic transconductances as high as 240 mS/mm were obtained. Although these devices had a drain current drift of 20% under DC bias, when operated at 5 GHz they exhibited negligible drain current drift. The observation of high transconductance and stable microwave performance makes these HIGFETs ideal candidates for microwave power applications     

Gate-length dependence of DC and microwave properties ofsubmicrometer In0.53Ga0.47As HIGFETs

In_0.52Al_0.48As/In_0.53Ga_0.47 As/InP heterostructure insulated-gate field-effect transistors (HIGFETs) with gate lengths from 1.1 and 0.3 μm have been fabricated, and their electrical performance is characterized at DC and microwave frequencies. The refractory-gate self-aligned process, applied to devices with In_0.53Ga_0.47As channels, yields an unprecedented combination of very-high speed and excellent uniformity. HIGFETs with L_g=0.6 μm showed average peak transconductance g_m of 528 mS/mm and unity-current-gain cutoff frequency f_t of 50 GHz. The uniformity of g_m was better than 1%, and the voltage of the g_m peak was uniform to ±30 mV. HIGFETs with L_g=0.3 μm showed f₁ up to 63 GHz, but suffered from serious short-channel effect, due to excessive thickness of the InGaAs channel layer. A self-aligned technique for gate resistance reduction is shown to substantially improve microwave power gain     

High-performance self-aligned (Al,Ga)As/(In,Ga)As pseudomorphicHIGFETs

Transconductance as high as 676 mS/mm at 300 K was observed to 0.7×10-μm² n-channel devices (HIGFETs) made on epilayers with Al_0.3Ga_0.7As insulator thickness of 200 Å and In_0.15Ga_0.85As channel thickness of 150 Å. An FET K value (K=W_g Uε/2aL_g) as large as 10.6 mA/V ² was also measured from another device with transconductance of 411 mS/mm. The high K values are achieved under normal FET operation without hole-injection or drain-avalanche breakdown effects. These results demonstrate the promise of pseudomorphic (Al,Ga)As/(In,Ga)As HIGFETs for high-performance circuit applications     

Dependence of current-gain cutoff frequency on gate length in submicron GaInAs/AlInAs MODFETs

Investigates the gate length (L/sub g/) dependence of the current-gain cutoff frequency f/sub T/ in lattice-matched GaInAs/AlInAs MODFETs. The transconductance is found to be relatively insensitive to gate length in this submicron regime, while the f/sub T/ increases with decreasing gate length due to reduced capacitance as dictated by the charge control model. An effective saturation velocity of 1.3*10/sup 7/ cm/s is deduced from the f/sub T/-L/sub g/ dependence. A maximum f/sub T/ of 112 GHz is measured on an L/sub g/=0.15 mu m device, limited mainly by parasitic charge in the AlInAs.<>     

Low-frequency noise characteristics of AlInAs/GaInAs modulation-doped field-effect transistors

The output noise voltage of AlInAs/GaInAs MODFETs grown by both MOCVD and MBE was measured at frequencies from 1 MHz to 1.5 GHz under different bias conditions for the first time. For frequencies below 500 MHz the noise voltage showed a 1/f dependence with a corner frequency around 200 MHz. The low-frequency noise was larger at the bias conditions giving higher transconductance.<>     

Reduced short-channel effects in submicron N-HIGFET technologyusing sidewalls

In this letter, 0.35 μm gate length pseudomorphic AlGaAs/InGaAs/GaAs heterostructure insulated-gate field-effect-transistors (HIGFETs) have been fabricated on GaAs. The short-channel effects have been reduced by using a sidewall technology. A high current density and a high transconductance were obtained, reflectively, 510 mA/mm and 550 mS/mm, in addition to a high value of extrinsic current gain cutoff frequency F_T=44 GHz. The dependencies of subthreshold current, threshold voltage, and output conductance on gate length have been emphasised     

Hot electron degradation effects in 0.14 μm AlInAs/GaInAs/InP HEMTs

We report on hot electron stress measurements on 0.14 μm MOCVD grown AlInAs/GaInAs/InP HEMTs. The stress measurements increase the drain-source current and hence induce a temporary negative shift in the threshold voltage in unpassivated HEMTs. A permanent negative shift in the threshold voltage has been obtained in passivated HEMTs. The observed degradation (temporary/permanent) is due to the storage of positive charges (created by the impact ionization in the channel) in the Schottky AlInAs layer (temporary) or at the interface of semiconductor-passivation layer (permanent). For a given drain-source bias, a shift in the threshold voltage is larger in the gate-source bias region where the device has a maximum transconductance value.     

W/WSi gate self-aligned HIFETs (heterointerface FETs) using anAlInAs/GaInAs heterostructure grown by MOCVD

An undoped AlInAs/GaInAs heterostructure was grown by MOCVD and a W/WSi gate self-aligned HIFET (heterointerface FET) structure was made by ion implantation and rapid thermal annealing. The HIFET, 5 μm in gate length, was of an enhancement-type with a threshold voltage of about 0 V and with a transconductance of 280 mS/mm at room temperature. This result confirms the very high potential of this device for direct coupled FET logic (DCFL)     

Metamorphic AlInAs/GaInAs HEMTs on GaAs Substrates by MOCVD

Metamorphic AlInAs/GaInAs high-electron mobility transistors with very good device performance have been grown by metal-organic chemical vapor deposition (MOCVD), with the introduction of an effective multistage buffering scheme. Measured room-temperature Hall mobilities of the 2-DEG were over 8000 cm²/V ldr s with sheet carrier densities larger than 4 times 10¹² cm^-2. Transistors with 1-mum gate length exhibited transconductance up to 626 mS/mm. The unity current gain cutoff frequency f_T and the maximum oscillation frequency f_max were 39.1 and 71 GHz, respectively. These results are very encouraging toward the manufacturing of metamorphic devices on GaAs substrates by MOCVD.     

i-GaAlAs/GaAs HIGFETs器件参数的有限元分析

本文用有限元法对 i-GaAlAs/GaAs HIGFETs的稳态特性进行了二维数值模拟和分析。为了在有限内存的微机中,进行快速计算,在程序中,对边界条件,网格剖分和初值选取等方面进行了改进。使计算的收敛速度和精度有了提高。可方便地得到器件内部的电位和载流子浓度等物理量的二维分布。其输出特性和实验数据基本吻合。     

Infrared reflection spectra of multilayer epitaxial heterostructures with embedded InAs and GaAs layers

The effect of the thickness of embedded InAs and GaAs layers on the infrared reflection spectra of lattice vibrations for AlInAs/InAs/AlInAs, InGaAs/GaAs/InGaAs, and AlInAs/InGaAs/GaAs/InGaAs/AlInAs multilayer epitaxial heterostructures grown by MOC hydride epitaxy on InP (100) substrates is studied. Relative stresses emerging in the layers surrounding the embedded layers with variation in the number of monolayers from which the quantum dots are formed and with variation the thickness of the layers themselves surrounding the embedded layers are evaluated.     

A 0.4-μm gate-length AlGaAs/GaAs P-channel HIGFET with 127-mS/mmtransconductance at 77 K

WN-gate, p-channel AlGaAs-GaAs heterostructure insulated-gate field-effect transistors (HIGFETs) fabricated on a metalorganic vapor-phase epitaxy (MOVPE) wafer are discussed. A self-aligned Mg ion implantation (80 keV, 6×10¹³ cm^-2) annealed at 850°C in an arsine atmosphere and the control of the SiO₂ sidewall dimensions allow the fabrication of p-channel HIGFETs with a gate length smaller than 0.5 μm with low subthreshold current. P-channel HIGFETs with 0.4-μm gate lengths exhibit extrinsic transconductances as high as 127 mS/mm at 77 K and 54 mS/mm at 300 K     

Design and Characteristics of Guardring-Free Planar AlInAs Avalanche Photodiodes

This paper reports a guardring-free planar AlInAs avalanche photodiode (APD) for optical fiber communications. AlInAs APDs can achieve a larger gain-bandwidth product (GBP) with lower excess noise than commercial InP APDs, and the guardring-free planar structure enables these superior AlInAs APDs to have both a low dark current and high reliability for practical use. We present the structure, fabrication, designs, APD characteristics, and receiver sensitivity, systematically. The guardring-free planar structure and its peculiarities are described, and we show APD designs for 2.5-Gb/s and 10-Gb/s applications and their characteristics. A 0.2-mum -thick AlInAs multiplication layer achieves a GBP of 120 GHz and an excess noise factor of 2.9 at a multiplication factor of 10. Their dark currents are less than 20 nA and their lifetime is evaluated to be 25 million hours at 85^degC. Lastly, we demonstrate that the guardring-free planar AlInAs APDs with a transimpedance amplifier achieve the remarkable sensitivity of -37.0 dBm at a bit error rate of 10^-10 for 2.5-Gb/s signals and of -29.9 dBm at a bit error rate of 10^-12 for 10-Gb/s signals. This performance indicates that the guardring-free planar AlInAs APDs have made great advances against commercial InP APDs and other AlInAs APDs.