在1．8GHz频率下功率密度为2．8W／mm的4H－SiCMESFET

本文论述了使用４Ｈ－ＳｉＣ衬底及外延层制作ＭＥＳＦＥＴ的方法，测得了栅长为０．７μｍ、栅宽为３３２μｍ的ＭＥＳＦＥＴ的直流、Ｓ参数和输出功率特性。当Ｖｄｓ＝２５Ｖ时，电流密度约为３００ｍＡ／ｍｍ，最大跨导在３８～４２ｍＳ／ｍｍ之间；当频率为５ＧＨｚ时，该器件的增益为９．３ｄＢ，ｆｍａｘ＝１２．９ＧＨｚ。当Ｖｄｓ＝５４Ｖ时，功率密度为２．８Ｗ／ｍｍ，功率附加效率为１２．７％。     

An InP MISFET with a power density of 1.8 W/mm at 30 GHz

The millimeter-wave power performance of a 75-μm×0.3-μm InP MISFET with SiO₂ insulator is presented. The combination of high intrinsic transconductance (120 mS/mm), current density (1 A/mm), and gate-source and gate-drain breakdown voltages (35 V) led to a record power density of 1.8 W/mm and 20% power-added efficiency at 30 GHz. This power density is the highest ever reported for any three-terminal device at this frequency     

AlGaN-GaN HEMTs on Si with power density performance of 1.9 W/mm at 10 GHz

AlGaN-GaN high electron mobility transistors (HEMTs) on silicon substrate are fabricated. The device with a gate length of 0.3-/spl mu/m and a total gate periphery of 300 /spl mu/m, exhibits a maximum drain current density of 925 mA/mm at V/sub GS/=0 V and V/sub DS/=5 V with an extrinsic transconductance (g/sub m/) of about 250 mS/mm. At 10 GHz, an output power density of 1.9 W/mm associated to a power-added efficiency of 18% and a linear gain of 16 dB are achieved at a drain bias of 30 V. To our knowledge, these power results represent the highest output power density ever reported at this frequency on GaN HEMT grown on silicon substrates.     

Record gain at 3.1 GHz of 4H-SiC high power RF MESFET

In this paper, a very high gain 4H-SiC power MESFET with incorporation of L-gate and source field plate (LSFP-MESFET) structures for high power and RF applications is proposed. The influence of L-gate and source field plate structures on saturation current, breakdown voltage (V_b) and small-signal characteristics of the LSFP-MESFET was studied by numerical device simulation. The optimized results showed that V_b of the LSFP-MESFET is 91% larger than that of the 4H-SiC conventional MESFET (C-MESFET), which meanwhile maintains almost 77% higher saturation drain current characteristics. The maximum output power densities of 21.8 and 5.5 W/mm are obtained for the LSFP-MESFET and C-MESFET, respectively, which means about 4 times larger output power for the proposed device. Also, the cut-off frequency (f_T) of 23.1 GHz and the maximum oscillation frequency (f_max) of 85.3 GHz for the 4H-SiC LSFP-MESFET are obtained compared to 9.4 and 36.2 GHz for that of the C-MESFET structure, respectively. The proposed LSFP-MESFET shows a new record maximum stable gain exceeding 22.7 dB at 3.1 GHz, which is 7.6 dB higher than that of the C-MESFET. To the best of our knowledge, this is 2.5 dB greater than the highest gain yet reported for SiC MESFETs, showing the potential of this device for high power RF applications.     

1 W/mm RF power density at 3.2 GHz for a dual-layer RESURF LDMOStransistor

In this letter, we present state-of-the-art performance, in terms of output power density, for an RF-power LDMOS transistor. The novel device structure has a dual-layer RESURF of the drift region, which allows for a sub-μm channel length and a high breakdown voltage of 110 V. The output power density is more than 2 W/mm at 1 GHz and a V_DS=70 V, with a stable gain of 23 dB at V_DS=50 V. At 3.2 GHz the power density is over 1 W/mm at V_DS=50 V and 0.6 W/mm at V_DS=28 V. These results are to our knowledge the best ever for silicon power MOSFETs     

A double-heterojunction doped-channel pseudomorphic power HEMT witha power density of 0.85 W/mm at 55 GHz

The authors report the DC characteristics and RF performances of a 50×0.2-μm² AlGaAs/InGaAs/GaAs pseudomorphic HEMT with a doped InGaAs channel. A transconductance as high as 760 mS/mm and a maximum current density of 800 mA/mm leads to a power density of 0.85 W/mm with 3.3-dB gain and 22.1% power-added efficiency at 55 GHz     

GaAs/AlGaAs heterojunction MISFET's having 1-W/mm power density at 18.5 GHz

The previously reported GaAs/AlGaAs heterojunction MISFET with an undoped AlGaAs layer as an insulator has been further optimized for power operation at upper Ku band. A 300-µm gate-width device generated 320 mW of output power with 33-percent efficiency at 18.5 GHz. The corresponding power density exceeds 1 W/mm. When optimized for efficiency, the device has achieved a power added efficiency of 43 percent at 19 GHz.     

Polyimide passivated AlGaN-GaN HFETs with 7.65 W/mm at 18 GHz

Current metal-organic chemical vapor deposition-grown AlGaN-GaN heterojunction field-effect transistor devices suffer from threading dislocations and surface states that form traps, degrading RF performance. A passivation scheme utilizing a polyimide film as the passivating layer was developed to reduce the number of surface states and minimize RF dispersion. Continuous-wave power measurements were taken at 18 GHz on two-finger 0.23-/spl mu/m devices with 2/spl times/75 /spl mu/m total gate width before and after passivation yielding an increase from 2.14 W/mm to 4.02 W/mm in power density, and 12.5% to 24.47% in power added efficiency. Additionally, a 2/spl times/25 /spl mu/m device yielded a peak power density of 7.65 W/mm at 18 GHz. This data suggests that polyimide can be an effective passivation film for reducing surface states.     

AlGaN-GaN HEMTs on SiC with CW power performance of >4 W/mm and 23% PAE at 35 GHz

In this work, continuous wave Ka-band power performance of AlGaN-GaN high electron-mobility transistors grown on semi-insulating SiC substrates are reported. The devices, with gate lengths of 0.25 /spl mu/m, exhibited maximum drain current density of 1.1 A/mm and peak extrinsic transconductance of 285 mS/mm. At 35 GHz, an output power density of 4.13 W/mm with 23% of power-added efficiency (PAE) and 7.54 dB of linear gain were achieved at a drain bias of 30 V. These power results represent the best power density, PAE, and gain combination reported at this frequency. The drain bias dependence of the Ka-band power performance of these devices is also presented.     

S-band operation of SiC power MESFET with 20 W (4.4 W/mm) output power and 60% PAE

Previous efforts have revealed instabilities in standard SiC MESFET device electrical characteristics, which have been attributed to charged surface states. This work describes the use of an undoped "spacer" layer on top of a SiC MESFET to form a "buried-channel" structure where the active current carrying channel is removed from the surface. By using this approach, the induced surface traps are physically removed from the channel region, such that the depletion depth caused by the unneutralized surface states cannot reach the conductive channel. This results in minimal RF dispersion ("gate lag") and, thus, improved RF performance. Furthermore, the buried-channel approach provides for a relatively broad and uniform transconductance (G/sub m/) with gate bias (V/sub gs/), resulting in higher efficiency MESFETs with improved linearity and lower signal distortion. SiC MESFETs having 4.8-mm gate periphery were fabricated using this buried-channel structure and were measured to have an output power of 21 W (P/sub out//spl sim/4.4 W/mm), 62% power added efficiency, and 10.6 dB power gain at 3 GHz under pulse operation. When operated at continuous wave, similar 4.8-mm gate periphery SiC MESFETs produced 9.2 W output power (P/sub out//spl sim/2 W/mm), 40% PAE, and /spl sim/7 dB associated gain at 3 GHz.     

10GHz 1W GaAs MESFET

<正> 一、引言自从1966年C. A. Mead提出肖特基场效应晶体管以来,GaAsMESFET作为一种微波器件受到广泛重视。短短十几年来已取得突飞猛进的发展。在4～20GHz的频率范围内,GaAs功率MESFET已被公认为是一种最好的微波功率器件。它具有结构简单、体积小、重量轻、功率大、效率高、线性好、频带宽等优点。在相控阵雷达、卫星和地面通信、电子对抗及卫星直播电视中得到广泛的运用,有着广阔的发展前景。     

GaAs power MESFET with 41-percent power-added efficiency at 35 GHz

A GaAs power MESFET has been optimized for Ka-Band operation. The device has an n⁺ ledge channel structure with a 0.25-μm gate on MBE-grown material. An output power density of 0.71 W/mm was achieved with 5.2-dB gain and 34% power-added efficiency. When tuned for maximum efficiency, a power-added efficiency of 41% was obtained with a power density of 0.61 W/mm and a gain of 5.6 dB     

Output power density of 5.1/mm at 18 GHz with an AlGaN/GaN HEMT on Si substrate

Microwave frequency capabilities of AlGaN/GaN high electron mobility transistors (HEMTs) on high resistive silicon (111) substrate for power applications are demonstrated in this letter. A maximum dc current density of 1 A/mm and an extrinsic current gain cutoff frequency (F/sub T/) of 50 GHz are achieved for a 0.25 /spl mu/m gate length device. Pulsed and large signal measurements show the good quality of the epilayer and the device processing. The trapping phenomena are minimized and consequently an output power density of 5.1 W/mm is reached at 18 GHz on a 2/spl times/50/spl times/0.25 /spl mu/m/sup 2/ HEMT with a power gain of 9.1dB.     

4H-SiC MESFET器件工艺

介绍了制作4H-SiC MESFET器件的关键工艺.通过改进工艺,采用半绝缘衬底的国产SiC三层外延片,制造出总栅宽为1mm,2GHz连续波下输出功率大于4W,小信号增益大于10dB的SiC MESFET.     

4H-SiC MESFET器件工艺

介绍了制作4H-SiC MESFET器件的关键工艺.通过改进工艺,采用半绝缘衬底的国产SiC三层外延片,制造出总栅宽为1mm,2GHz连续波下输出功率大于4W,小信号增益大于10dB的SiC MESFET.     

4H-SiC MESFET's with 42 GHz fmax

We report for the first time the development of state-of-the-art SiC MESFETs on high-resistivity 4H-SiC substrates. 0.5 μm gate MESFETs in this material show a new record high f_max of 42 GHz and RF gain of 5.1 dB at 20 GHz. These devices also show simultaneously high drain current, and gate-drain breakdown voltage of 500 mA/mm, and 100 V, respectively showing their potential for RF power applications     

1.8GHz 0.35mm CMOS低噪声放大器的实现

介绍了一种频率为1.8GHz的低噪声放大器(LNA)的设计方案,采用TSMC 0.35μm CMOS工艺实现,增益为25dB,噪声系数2.56dB,功耗≤10mW,IIP3为-25dB或5dBm。     

4H-SiC MESFET结构外延生长技术

利用热壁式CVD技术生长4H-SiC MESFET结构外延材料,TMA和氮气分别用作p型和n型掺杂源.外延层厚度使用SEM进行表征,SIMS及汞探针C-V用作外延层掺杂浓度测试.通过优化生长参数,成功生长出高质量的MESFET结构外延材料并获得陡峭的过渡掺杂曲线,并给出了部分器件测试结果.     

4H-SiC MESFET结构外延生长技术

利用热壁式CVD技术生长4H-SiC MESFET结构外延材料,TMA和氮气分别用作p型和n型掺杂源.外延层厚度使用SEM进行表征,SIMS及汞探针C-V用作外延层掺杂浓度测试.通过优化生长参数,成功生长出高质量的MESFET结构外延材料并获得陡峭的过渡掺杂曲线,并给出了部分器件测试结果.     

8.9W/mm高功率密度SiC MESFET器件研制

基于自主研发的碳化硅(SiC)材料外延技术,优化了材料各层结构及参数,减小了Al记忆效应,最终得到了高质量SiC外延片。采用自主研发成熟的SiC MESFET工艺平台,制作了多凹栅器件结构,优化了凹槽尺寸,采用细栅制作技术完成了栅电极制作,最终得到了不同栅宽的SiC MESFET芯片。突破了大栅宽芯片流片、封装及大功率脉冲测试技术,研制成功了微波功率特性良好的MESFET器件。微波测试结果表明,在2 GHz脉冲条件下,0.25 mm栅宽器件,输出功率密度达到8.96 W/mm,功率附加效率达到30%。单胞20 mm大栅宽器件,3.4 GHz脉冲条件下,功率输出达到94 W,功率附加效率达到22.4%。