具有136GHz的0.18m GaAs Metamorphic HEMT器件

应用电子束直写技术成功制作了栅长0.18μm的高性能In0.52Al0.48As/In0.53Ga0.47As MHEMT。从工艺角度,结合器件的小信号等效电路的理论分析,优化了器件结构,特别是T形栅结构,从而减小了器件寄生参数,达到了较好的器件性能。最终制作的In0.52Al0.48As/In0.53Ga0.47As MHEMT饱和电流达到275mA/mm,夹断电压-0.8V,在Vgs为-0.15V时的最大非本征跨导gm为650mS/mm,截止频率ft达到136GHz,最大振荡频率fmax大于120GHz。     

60-GHz high power performance In/sub 0.35/Al/sub 0.65/As-In/sub 0-35/Ga/sub 0.65/As metamorphic HEMTs on GaAs

We report on a double-pulse doped, double recess In/sub 0.35/Al/sub 0.65/As-In/sub 0.35/Ga/sub 0.65/As metamorphic high electron mobility transistor (MHEMT) on GaAs substrate. This 0.15-/spl mu/m gate MHEMT exhibits excellent de characteristics, high current density of 750 mA/mm, extrinsic transconductance of 700 mS/mm. The on and off state breakdown are respectively of 5 and 13 V and defined It gate current density of 1 mA/mm. Power measurements at 60 GHz were performed on these devices. Biased between 2 and 5 V, they demonstrated a maximum output power of 390 mW/mm at 3.1 V of drain voltage with 2.8 dB power gain and a power added efficiency (PAE) of 18%. The output power at 1 dB gain compression is still of 300 mW/mm. Moreover, the linear power gain is of 5.2 dB. This is to our knowledge the best output power density of any MHEMT reported at this frequency.     

Low noiseIn0.32(AlGa)0.68As/In0.43Ga0.57As metamorphic HEMT on GaAs substrate with 850 mW/mm output powerdensity

A double-pulse-doped InAlGaAs/In_0.43Ga_0.57As metamorphic high electron mobility transistor (MHEMT) on a GaAs substrate is demonstrated with state-of-the-art noise and power performance, This 0.15 μm T-gate MHEMT exhibits high on- and off-state breakdown (V_ds>6 V and V_dg>13 V, respectively) which allows biasing at V_ds>5 V. The 0.6 mm device shows >27 dBm output power (850 mW/mm) at 35 GHz-the highest reported power density of any MHEMT. Additionally, a smaller gate periphery 2×50 μm (0.1 mm) 43% MHEMT exhibits a F_min=1.18 dB and 10.7 dB associated gain at 25 GHz, and also is the first noise measurement of a -40% In MHEMT. A double recess process with selective etch chemistries provides for high yields     

156GHz 0.15μm GaAs Metamorphic HEMT器件研制

应用电子束直写技术成功制作了栅长0.15μm的高性能In0.52Al0.48As/In0.53Ga0.47As GaAs MHEMT。从工艺角度,结合器件的小信号等效电路的理论分析,优化了器件源漏间距,从而减小了器件寄生参数,达到了较好的器件性能。最终制作的In0.52Al0.48As/In0.53Ga0.47As MHEMT饱和电流达到495mA/mm,夹断电压-0.8V,在Vgs为-0.19V时的最大非本征跨导gm为1032mS/mm,截止频率ft达到156GHz,最大振荡频率fmax大于150GHz。     

2 V-operated InGaP-AlGaAs-InGaAs enhancement-mode pseudomorphic HEMT

A low-voltage single power supply enhancement-mode InGaP-AlGaAs-InGaAs pseudomorphic high-electron mobility transistor (PHEMT) is reported for the first time. The fabricated 0.5/spl times/160 /spl mu/m/sup 2/ device shows low knee voltage of 0.3 V, drain-source current (I/sub DS/) of 375 mA/mm and maximum transconductance of 550 mS/mm when drain-source voltage (V/sub DS/) was 2.5 V. High-frequency performance was also achieved; the cut-off frequency(F/sub t/) is 60 GHz and maximum oscillation frequency(F/sub max/) is 128 GHz. The noise figure of the 160-/spl mu/m gate width device at 17 GHz was measured to be 1.02 dB with 10.12 dB associated gain. The E-mode InGaP-AlGaAs-InGaAs PHEMT exhibits a high output power density of 453 mW/mm with a high linear gain of 30.5 dB at 2.4 GHz. The E-mode PHEMT can also achieve a high maximum power added efficiency (PAE) of 70%, when tuned for maximum PAE.     

DC and RF performance of LP-MOCVD grownAl0.25Ga0.75As/InxGa1-xAs(x=0.15-0.28) P-HEMT's with Si-delta doped GaAs layer

Si-delta-doped Al_0.25Ga_0.75As/In_xGa_1-xAs (x=0.15-0.28) P-HEMT's, prepared by LP-MOCVD, are investigated. The large conduction band discontinuity leads to 2-DEG density as high as 2.1×10¹²/cm² with an electron mobility of 7300 cm²/V·s at 300 K. The P-HEMT's with 0.7×60 μm gate have a maximum extrinsic transconductance of 380 mS/mm, and a maximum current density of 300 mA/mm. The S-parameter measurements indicate that the current gain and power gain cutoff frequencies are 30 and 61 GHz, respectively, The RF noise characteristics exhibit a minimum noise figure of 1.2 dB with an associated gain of 10 dB at 10 GHz. Due to the efficient doping technique, the electron mobility and transconductance obtained are among the best reported for MOCVD grown P-HEMT's with the similar structure     

InAlAs/InGaAs metamorphic HEMT with high current density and highbreakdown voltage

An In_0.3Al_0.7As/In_0.3Ga_0.7 As metamorphic power high electron mobility transistor (HEMT) grown on GaAs has been developed. This structure with 30% indium content presents several advantages over P-HEMT on GaAs and LM-HEMT on InP. A 0.15-μm gate length device with a single δ doping exhibits a state-of-the-art current gain cut-off frequency F_t value of 125 GHz at V_ds=1.5 V, an extrinsic transconductance of 650 mS/mm and a current density of 750 mA/mm associated to a high breakdown voltage of -13 V, power measurements performed at 60 GHz demonstrate a maximum output power of 240 mW/mm with 6.4-dB power gain and a power added efficiency (PAE) of 25%. These are the first power results ever reported for any metamorphic HEMT     

High-performance double-recessed enhancement-mode metamorphic HEMTs on 4-in GaAs substrates

Enhancement-mode InAlAs/InGaAs/GaAs metamorphic HEMTs with a composite InGaAs channel and double-recessed 0.15-/spl mu/m gate length are presented. Epilayers with a room-temperature mobility of 10 000 cm/sup 2//V-s and a sheet charge of 3.5/spl times/10/sup 12/cm/sup -2/ are grown using molecular beam epitaxy on 4-in GaAs substrates. Fully selective double-recess and buried Pt-gate processes are employed to realize uniform and true enhancement-mode operation. Excellent dc and RF characteristics are achieved with threshold voltage, maximum drain current, extrinsic transconductance, and cutoff frequency of 0.3 V, 500 mA/mm, 850 mS/mm, and 128 GHz, respectively, as measured on 100-/spl mu/m gate width devices. The load pull measurements of 300-/spl mu/m gate width devices at 35 GHz yielded a 1-dB compression point output power density of 580 mW/mm, gain of 7.2 dB, and a power-added efficiency of 44% at 5 V of drain bias.     

Millimeter-wave low-noise and high-power metamorphic HEMTamplifiers and devices on GaAs substrates

This paper reports on state of-the-art HEMT devices and circuit results utilizing 32% and 60% indium content InGaAs channel metamorphic technology on GaAs substrates. The 60% In metamorphic HEMT (MHEMT) has achieved an excellent 0.61-dB minimum noise figure with 11.8 dB of associated gain at 26 GHz. Using this MHEMT technology, two and three-stage Ka-band low-noise amplifiers (LNAs) have demonstrated <1.4-dB noise figure with 16 dB of gain and <1.7 with 26 dB of gain, respectively. The 32% In MHEMT device has overcome the <3.5-V drain bias limitation of other MHEMT power devices, showing a power density of 650 mW/mm at 35 GHz, with V_ds=6 V     

0.1-µm Gate-length pseudomorphic HEMT's

AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistors (HEMT's) with a gate length of 0.1 µm have been successfully fabricated. The HEMT's exhibit a maximum transconductance of 540 mS/mm with excellent pinch-off characteristics. A maximum stable gain (MSG) as high as 18.2 dB was measured at 18 GHz. At 60 GHz the device has demonstrated a minimum noise figure of 2.4 dB with an associated gain of ∼6 dB. These are the best gain and noise results reported to date for HEMT's.     

High-performance GaAs MESFETs with advanced LDD structure fordigital, analog, and microwave applications

GaAs MESFETs with advanced LDD structure have been developed by using a single resist-layered dummy gate (SRD) process. The advanced LDD structure suppresses the short channel effects, and reduces source resistance, while maintaining a moderate breakdown voltage. The 0.3-μm enhancement-mode devices exhibit a transconductance of 420 mS/mm, while the breakdown voltage of the depletion-mode device (V_th=-500 mV) is larger than 6 V. The standard deviation of the threshold voltage for 0.3-μm devices is less than 30 mV across a 3-in wafer. The 0.3-μm devices exhibit an average cutoff frequency of 47.2 GHz with a standard deviation of 1.3 GHz across a 3-in wafer. The cutoff frequency of a 0.15-μm device is as high as 72 GHz. D-type flip-flop circuits for digital IC applications and preamplifier for analog IC applications fabricated with 0.3-μm gate length devices operate above 10 Gb/s. In addition, the 0.3-μm devices also show good noise performance with a noise figure of 1.1 dB with associated gain of 6.5 dB at 18 GHz. These results demonstrate that GaAs MESFETs with an advanced LDD structure are quite suitable for digital, analog, microwave, and hybrid IC applications     

W-band low-noise InAlAs/InGaAs lattice-matched HEMTs

Very low-noise 0.15-μm gate-length W-band In_0.52 Al_0.48As/In_0.53Ga_0.47As/In _0.52Al_0.48As/InP lattice-matched HEMTs are discussed. A maximum extrinsic transconductance of 1300 mS/mm has been measured for the device. At 18 GHz, a noise figure of 0.3 dB with an associated gain of 17.2 dB was measured. The device also exhibited a minimum noise figure of 1.4 dB with 6.6-dB associated gain at 93 GHz. A maximum available gain of 12.6 dB at 95 GHz, corresponding to a maximum frequency of oscillation, f_max, of 405 GHz (-6-dB/octave extrapolation) in the device was measured. These are the best device results yet reported. These results clearly demonstrate the potential of the InP-based HEMTs for low-noise applications, at least up to 100 GHz     

50-nm T-Gate InAlAs/InGaAs Metamorphic HEMTs With Low Noise and High fT Characteristics

We report 50-nm T-gate metamorphic high-electron mobility transistors (MHEMTs) with low noise figure and high characteristics. The 30 mumtimes2 MHEMT shows a drain current density of 690 mA/mm, a g_m,max of 1270 mS/mm, an f_T of 489 GHz, and an of 422 GHz. In the frequency range of 59-61 GHz, the noise figure is less than 0.7 dB, and the associated gain was greater than 9 dB at a drain voltage of 1.3 V and a gate voltage of -0.8 V. To our knowledge, the MHEMT shows the best performance in terms of and noise figure among GaAs-based HEMTs.     

Very high gain millimeter-wave InAlAs/InGaAs/GaAs metamorphicHEMT's

We report the first demonstration of W-band metamorphic HEMTs/LNA MMICs using an AlGaAsSb lattice strain relief buffer layer on a GaAs substrate. 0.1×50 μm low-noise devices have shown typical extrinsic transconductance of 850 mS/mm with high maximum drain current of 700 mA/mm and gate-drain breakdown voltage of 4.5 V. Small-signal S-parameter measurements performed on the 0.1-μm devices exhibited an excellent f_T of 225 GHz and maximum stable gain (MSG) of 12.9 dB at 60 GHz and 10.4 dB at 110 GHz. The three-stage W-band LNA MMIC exhibits 4.2 dB noise figure with 18 dB gain at 82 GHz and 4.8 dB noise figure with 14 dB gain at 89 GHz, The gain and noise performance of the metamorphic HEMT technology is very close to that of the InP-based HEMT     

A Ku-band T-shaped gate GaAs power MESFET with high breakdownvoltage for satellite communications

^GaAs power MESFET's with 0.5-μm T-shaped gate for Ku-band power applications have been developed using a new self-aligned and optical lithography. It displays a maximum current density of 350 mA/mm, an uniform transconductance of 150 mS/mm and a high gate-to-drain breakdown voltage of 35 V. Both the high breakdown voltage and the uniform transconductance were achieved by the new MESFET design incorporating an undoped GaAs cap and a thick lightly doped active layers. The breakdown voltage is the highest one among the values reported on the power devices. The device exhibits 0.61 W/mm power density and 47% power added efficiency with 9.0 dB associated gain at a drain bias of 12 V and an operation frequency of 12 GHz     

DC and RF characteristics of E-mode Ga/sub 0.51/In/sub 0.49/P-In/sub 0.15/Ga/sub 0.85/As pseudomorphic HEMTs

The DC and RF characteristics of Ga/sub 0.49/In/sub 0.51/P-In/sub 0.15/Ga/sub 0.85/As enhancement- mode pseudomorphic HEMTs (pHEMTs) are reported for the first time. The transistor has a gate length of 0.8 /spl mu/m and a gate width of 200 /spl mu/m. It is found that the device can be operated with gate voltage up to 1.6 V, which corresponds to a high drain-source current (I/sub DS/) of 340 mA/mm when the drain-source voltage (V/sub DS/) is 4.0 V. The measured maximum transconductance, current gain cut-off frequency, and maximum oscillation frequency are 255.2 mS/mm, 20.6 GHz, and 40 GHz, respectively. When this device is operated at 1.9 GHz under class-AB bias condition, a 14.7-dBm (148.6 mW/mm) saturated power with a power-added efficiency of 50% is achieved when the drain voltage is 3.5 V. The measured F/sub min/ is 0.74 dB under I/sub DS/=15 mA and V/sub DS/=2 V.     

High performance 0.1 μm gate-length p-type SiGe MODFET's andMOS-MODFET's

High performance p-type modulation-doped field-effect transistors (MODFET's) and metal-oxide-semiconductor MODFET (MOS-MODFET) with 0.1 μm gate-length have been fabricated on a high hole mobility SiGe-Si heterojunction grown by ultrahigh vacuum chemical vapor deposition. The MODFET devices exhibited an extrinsic transconductance (g_m) of 142 mS/mm, a unity current gain cut-off frequency (f_T) of 45 GHz and a maximum oscillation frequency (f_MAX) of 81 GHz, 5 nm-thick high quality jet-vapor-deposited (JVD) SiO₂ was utilized as gate dielectric for the MOS-MODFET's. The devices exhibited a lower gate leakage current (1 nA/μm at V_gs=6 V) and a wider gate operating voltage swing in comparison to the MODFET's. However, due to the larger gate-to-channel distance and the existence of a parasitic surface channel, MOS-MODFET's demonstrated a smaller peak g _m of 90 mS/mm, f_T of 38 GHz, and f_max of 64 GHz. The threshold voltage shifted from 0.45 V for MODFET's to 1.33 V for MOS-MODFET's. A minimum noise figure (NF_min) of 1.29 dB and an associated power gain (G_a) of 12.8 dB were measured at 2 GHz for MODFET's, while the MOS-MODFET's exhibited a NF _min of 0.92 dB and a G_a of 12 dB at 2 GHz. These DC, RF, and high frequency noise characteristics make SiGe/Si MODFET's and MOS-MODFET's excellent candidates for wireless communications     

T形栅In0.52Al0.48As/In0.6Ga0.4As MHEMTs功率器件

利用电子束光刻技术制备了200nm栅长GaAs基T型栅InAlAs/lnGaAs MHEMT器件.该GaAs基MHEMT器件具有优越的直流、高频和功率性能,跨导、饱和漏电流密度、阈值电压、电流增益截止频率和最大振荡频率分别达到510mS/mm,605mA/mm,-1.8V,138GHz和78GHz.在8GHz下,输人功率为-0.88(2.11)dBm时,输出功率、增益、PAE、输出功率密度分别为14.05(13.79)dBm,14.9(11.68)dB,67.74(75.1)%,254(239)mW/mm,为进一步研究高性能GaAs基MHEMT功率器件奠定了基础.     

High-efficiency GaAs power MESFETs prepared by ion implantation

GaAs power MESFETs have been fabricated using ion implantation to form channel layers. A 1 ?m gate length by 2400 ?m gate width device has demonstrated an output power of 1.63 W with 6.9 dB associated gain, 35% power-added efficiency and 9.7 dB linear gain at 10 GHz. The transconductance of this device is 280 mS, which corresponds to 117 mS/mm. This result demonstrates that excellent GaAs power MESFETs can be made by ion implantation, and is comparable to average results demonstrated by devices made by AsCl3 vapour phase epitaxy.     

Pseudomorphic AlGaAs/InGaAs/GaAs High Electron Mobility Transistors with Super Low Noise Performances of 0.41 dB at 18 GHz

Fully passivated low noise AlGaAs/InGaAs/GaAs pseudomorphic (PM) HEMT with wide head T-shaped gates were fabricated by dose split electron beam lithography (DSL). The dimensions of gate head and footprint were optimized by controlling the splitted pattern size, dose, and spaces of each pattern. We obtained stable T-shaped gate of 0.15 μm gate length with 1.35 μm-wide head. The maximum extrinsic transconductance was 560 mS/mm. The minimum noise figure measured at 18 GHz at V_ds = 2 V and I_ds = 17 mA was 0.41 dB with associated gain of 8.19 dB. At 12 GHz, the minimum noise figure and an associated gain were 0.26 and 10.25 dB, respectively. These noise figures are the lowest values ever reported for GaAs-based HEMTs. These results are attributed to the extremely low gate resistance of wide head T-shaped gate having a ratio of the head to footprint dimensions larger than 9.