Ion-implanted GaAs/AlGaAs heterojunction FET's grown by MOCVD

The successful fabrication of an ion-implanted GaAs/AlGaAs heterojunction FET device is discussed. Half-micrometer gate-length FET devices are fabricated by ion implantation into GaAs/AlGa heterostructures grown by metalorganic chemical vapor deposition (MOCVD) on 3-in-diameter GaAs substrates. The FET device exhibits a maximum extrinsic transconductance of 280 mS/mm with reduced transconductance variation over 2 V of gate bias. Excellent microwave performance is achieved with an f_t of 40 GHz, which is comparable to results obtained from 0.25-μm gate GaAs MESFETs. The effects of ion implantation on the heterojunction and corresponding device characteristics are also discussed     

GaAs自对准高温栅全离子注入运放差分输入电路研究

本文主要从事GaAs自对准高温栅全离子注入技术(SAG)的研究,并以此工艺为基础,制作了WSi_xN_y/GaAs SBD,栅长分别是0.8μm和0.5μm的MESFET和GaAs.高速运算放大器差分输入电路.其中制造的耗尽型MESFET,栅长0.8μm,栅宽25μm,夹断电压V_P=-2.5V,跨导gm达170mS/mm栅宽,饱和压降V_(dss)仅0.7V,漏源击穿电压BV_(dx)达6V.制造的GaAs运放差分输入电路,最大直流增益30dB,在1GHz下仍有29dB的增益,平均直流增益22dB,输入失偏较小,电源8～12V可调,其性能达国外1985年实验室研制水平.在电路设计中,采用SPICE3a7程序,成功地进行了GaAs差分输入电路模拟和设计.     

60-GHz power performance of ion-implantedInxGa(1-x/)AsGaAs MESFETs

State-of-the-art 60-GHz power performance is reported for ion-implanted InGaAs/GaAs MESFETs with 0.25×200-μm gate length. At output power of 100 mW, a power-added efficiency of 15% and associated gain of 4.2 dB were obtained and a saturated output power of 121 mW was achieved for the same device. These results are comparable to the best reported millimeter-wave power performance of InGaAs/GaAs pseudomorphic HEMTs     

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     

Super-low-noise performance of direct-ion-implanted 0.25-μm-gateGaAs MESFET's

The authors report on advanced ion implantation GaAs MESFET technology using a 0.25-μm `T' gate for super-low-noise microwave and millimeter-wave IC applications. The 0.25×200-μm-gate GaAs MESFETs achieved 0.56-dB noise figure with 13.1-dB associated gain at 50% I_DSS and 0.6 dB noise figure with 16.5-dB associated gain at 100% I_DSS at a measured frequency of 10 GHz. The measured noise figure is comparable to the best noise performance of AlGaAs/GaAs HEMTs and AlGaAs/InGaAs/GaAs pseudomorphic HEMTs     

GaAs power MESFETs prepared by metalorganic chemical vapour deposition

GaAs power MESFETs have been developed by using MOCVD wafers. The saturation current of 7.2 mm-wide MESFET chips fabricated on a 6 cm2 wafer has been found to have a standard deviation of 6.8%, which is nearly a half of that observed for MESFETs fabricated on a conventional VPE wafer of the same size. The two-chip device with a gate width of 14.4 mm delivered 4 W at 7.8 GHz with 3 dB gain. The output power of 4 W at 7.8 GHz is the state-of-the-art performance of the GaAs power MESFETs prepared by the MOCVD technique.     

Ku波段高功率GaAs FET

报导Ｋｕ波段高功率ＧａＡｓＦＥＴ的制造技术，包括全离子注入、０．５μｍ自对准栅、高可靠欧姆接触、干法生长和刻蚀、背面通孔、内匹配和合成技术。器件由两个９．６ｍｍ栅宽的芯片组成，在１１．２～１１．７ＧＨｚ频带内，一分口增益压缩输出功率８Ｗ，增益６ｄＢ，功率附加效率２４％。     

DC and RF performance of GaAs MESFET fabricated on silicon substrate using epitaxial lift-off technique

GaAs MESFETs have been fabricated on a silicon substrate using a molecular beam epitaxy grown film detached from its growth substrate and attached on a silicon substrate covered with a dielectric. The device processing is done on the silicon substrate. The MESFETs exhibit I/sub DSS/=130 mA/mm, g/sub m/=135 mS/mm and for 1.3 mu m gate length unity current gain cut-off frequency f/sub T/ of 12 GHz. Excellent device isolation with subpicoampere leakage currents is obtained.<>     

High performance pseudomorphic InGaP/InGaAs power HEMTs

Power transistors with a low d.c. supply voltage were demonstrated with pseudomorphic InGaP/In_0.2Ga_0.8As/GaAs heterostructure field effect transistors on GaAs substrates and 1 μm gate length technology. A current density of 200 mA mm⁻¹ and an extrinsic transconductance of 300 mS mm⁻¹ were exhibited on a 400 μm gate width process control monitor device. For a 1 cm gate width device measured at 850 MHz and V_ds = 1.3 V, state-of-the-art results, 57.4% for the PAE, 12.7 dB for the linear gain and 21.5 dBm for the output power, were obtained.     

GaAs heterojunction f.e.t. with epitaxial Ge gate

A Ge heterojunction-gate GaAs f.e.t. has been developed using p-type epitaxial Ge gates deposited by vacuum evaporation on heated n-type GaAs substrates. Boron-ion implantation of the gate and an aluminium overlay was used to lower the gate resistance. A typical 8 ?m gate-length device exhibited a noise figure of 5.2 dB with 4.5 dB associated gain at 1.8 GHz.     

Millimeter-wave ion-implanted gradedInxGa1-xAs MESFETs grown by MOCVD

The authors present the fabrication and characterization of ion-implanted graded In_xGa_1-xAs/GaAs MESFETs. The In_xGa_1-xAs layers are grown on GaAs substrates by MOCVD (metal-organic chemical vapor deposition) with InAs concentration graded from 15% at the substrate to 0% at the surface. 0.5-μm gate MESFETs are fabricated on these wafers using silicon ion implantation. In addition to improved Schottky contact, the graded In_xGa _1-xAs MESFET achieves maximum extrinsic transconductance of 460 mS/mm and a current-gain cutoff frequency f_t of 61 GHz, which is the highest ever reported for a 0.5-μm gate MESFET. In comparison, In_0.1Ga_0.9As MESFETs fabricated with the same processing technique show an f_t of 55 GHz     

High DC and microwave characteristics of subhalf-micrometre gate ion-implanted GaAs MESFETs using trilayer deep UV lithography

Subhalf-micrometre gate length ion-implanted GaAs MESFETs have been fabricated on 3 inch diameter substrates using trilayer deep UV lithography. Implanted MESFETs with 0.3 mu m gate lengths exhibit a maximum extrinsic transconductance of 205 mS/mm at a drain current of 600 mA/mm. From S-parameter measurements, a current gain cutoff frequency f/sub t/ of 56 GHz and a maximum available gain cutoff frequency f/sub max/ greater than 90 GHz are achieved. The gate-to-drain diode characteristics of the devices show a sharp breakdown voltage of 13-15 V. The high drain current-drain voltage and microwave characteristics indicate that ion-implanted technology with trilayer deep UV lithography has potential for the manufacture of power devices and amplifiers for Q-band communication applications. This is the first reported result using trilayer deep UV lithography to demonstrate both f/sub t/ over 56 GHz and 13-15 V gate-to-drain breakdown on 0.3 mu m gate-length ion-implanted GaAs MESFETs.<>     

2～12GHz GaAs单片行波放大器

报道了一个全平面超宽带ＧａＡｓ单片行波放大器的研究结果。该单片电路的核心部件是四个３００μｍ栅宽的ＭＥＳＦＥＴ，整个电路拓扑结构简单，芯片面积为３．０ｍｍ×１．８ｍｍ。电路经优化设计后在２～１２ＧＨｚ范围内，小信号增益为５±１ｄＢ，输入输出电压驻波比≤１．７５。上述频率范围内输出功率≥１６ｄＢｍ，噪声系数≤８ｄＢ。采用全离子注入、全平面工艺，均匀性、一致性良好。实验结果与设计预计值十分一致。     

VHF高压双栅功率MOSFET的研制

采用硅栅结构的自对准离子注入工艺,研制成功了源漏击穿电压ＢＶＤＳ为１２０Ｖ、输出功率５．１Ｗ、功率增益８ｄＢ、跨导６５０ｍＳ、截止频率ｆＴ为２７０ＭＨｚ的高压双栅功率ＭＯＳＦＥＴ器件。介绍了器件结构参数和工艺参数的设计,给出了计算机数值分析结果。     

Extremely low-noise performance of GaAs MESFETs with wide-headT-shaped gate

Fully ion-implanted low-noise GaAs MESFETs with a 0.11-μm Au/WSiN T-shaped gate have been successfully developed for applications in monolithic microwave and millimeter-wave integrated circuits (MMICs). In order to reduce the gate resistance, a wide Au gate head made of a first-level interconnect is employed. As the wide gate head results in parasitic capacitance, the relation between the gate head length (L_h) and the device performance is examined. The gate resistance is also precisely calculated using the cold FET technique and Mahon and Anhold's method. A current gain cutoff frequency (f_T) and a maximum stable gain (MSG) decrease monotonously as L_h increases on account of parasitic capacitance. However, the device with L_h of 1.0 μm, which has lower gate resistance than 1.0 Ω, exhibits a noise figure of 0.78 dB with an associated gain of 8.7 dB at an operating frequency of 26 GHz. The measured noise figure is comparable to that of GaAs-based HEMT's     

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.     

AlGaAs/GaAs Heterojunction bipolar power transistors

An AlGaAs/GaAs heterojunction bipolar transistor with a total emitter periphery of 320 ?m has been developed for power amplifier applications. For the base contact, Zn diffusion was used to convert the n-type emitter material into p-type with a doping of ?1.0 × 1020 cm?3. Because of the highly doped layer, contact resistivity was extremely low (5 × 10?7 ?cm2). At 3 GHz, a CW output power of 320 mW with 7 dB gain and 30% power-added efficiency was obtained. Under pulsed operation, the output power increased to 500 mW with 6 dB gain and 40% power-added efficiency. With further device structure optimisations, the power performance of heterojunction bipolar transistors is expected to rival, or even surpass, that of the GaAs MESFETs.     

High microwave and ultra-low noise performance of fullyion-implanted GaAs MESFETs with Au/WSiN T-shaped gate

Fully ion-implanted n⁺ self-aligned GaAs MESFETs with high microwave and ultra-low-noise performance have been fabricated. T-shaped gate structures composed of Au/WSiN are employed to reduce gate resistance effectively. A very thin and high-quality channel with high carrier concentration can be formed by adopting the optimum annealing temperature for the channel, and the channel surface suffers almost no damage by using ECR plasma RIE for gate formation. GaAs MESFETs with a gate length as short as 0.35 μm demonstrated a maximum oscillation frequency of 76 GHz. At an operating frequency of 18 GHz, a minimum noise figure of 0.81 dB with an associated gain of 7.7 dB is obtained. A K_f factor of 1.4 estimated by Fukui's noise figure equation, which is comparable to those of AlGaAs/GaAs HEMTs with the same geometry, reveals that the quality of the channel is very high     

DC and RF Characteristics of 0.15 pm Power Metamorphic HEMTs

DC and RF characteristics of 0.15 °m GaAs power metamorphic high electron mobility transistors (MHEMT) have been investigated. The 0.15 °m ° 100 °m MHEMT device shows a drain saturation current of 480 mA/mm, an extrinsic transconductance of 830 mS/mm, and a threshold voltage of ‐0.65 V. Uniformities of the threshold voltage and the maximum extrinsic transconductance across a 4‐inch wafer were 8.3% and 5.1%, respectively. The obtained cut‐off frequency and maximum frequency of oscillation are 141 GHz and 243 GHz, respectively. The 8 ° 50 °m MHEMT device shows 33.2% power‐added efficiency, an 18.1 dB power gain, and a 28.2 mW output power. A very low minimum noise figure of 0.79 dB and an associated gain of 10.56 dB at 26 GHz are obtained for the power MHEMT with an indium content of 53% in the InGaAs channel. This excellent noise characteristic is attributed to the drastic reduction of gate resistance by the T‐shaped gate with a wide head and improved device performance. This power MHEMT technology can be used toward 77 GHz band applications.     

Extremely low-noise MESFETs fabricated by metal-organic chemical vapour deposition

Quarter-micron gate low-noise GaAs MESFETs have been developed by delineating gate electrodes by an electron-beam lithography technique and by using high-purity epiwafers prepared by a metal-organic-chemical vapour deposition (MOCVD) technique. At 18 GHz, a noise figure of 1.75 dB with an associated gain of 8.5 dB and a maximum available gain of 11 dB were obtained at drain currents of 10 mA and 30 mA, respectively. This is the lowest noise figure yet reported for low-noise GaAs MESFETs.