Device Characteristics Comparison Between GaAs Single and Double Delta-Doped Pseudomorphic High Electron Mobility Transistors

The Al 0.24Ga 0.76As/In 0.22Ga 0.78As single delta-doped PHEMT (SH-PHEMT) and double delta-doped PHEMT (DH-PHEMT) are fabricated and investigated.Based on the employment of double heterojunction,double delta doped design,the DH-PHEMT can enhance the carrier confinement,increase the electron gas density,and improve the electron gas distribution,which is beneficial to the device performance.A high device linearity,high transconductance over a large gate voltage swing,high current drivability are found in DH-PHEMT.These improvements suggest that DH-PHEMT is more suitable for high linearity applications in microwave power device.

C band microwave damage characteristics of pseudomorphic high electron mobility transistor

The damage effect characteristics of GaAs pseudomorphic high electron mobility transistor(pHEMT)under the irradiation of C band high-power microwave(HPM)is investigated in this paper.Based on the theoretical analysis,the thermoelectric coupling model is established,and the key damage parameters of the device under typical pulse conditions are predicted,including the damage location,damage power,etc.By the injection effect test and device microanatomy analysis through using scanning electron microscope(SEM)and energy dispersive spectrometer(EDS),it is concluded that the gate metal in the first stage of the device is the vulnerable to HPM damage,especially the side below the gate near the source.The damage power in the injection test is about 40 dBm and in good agreement with the simulation result.This work has a certain reference value for microwave damage assessment of pHEMT.

Enhancement of terahertz coupling efficiency by improved antenna design in GaN/AlGaN high electron mobility transistor detectors

An optimized micro-gated terahertz detector with novel triple resonant antenna is presented.The novel resonant antenna operates at room temperature and shows more than a 700% increase in photocurrent response compared to the conventional bowtie antenna.In finite-difference-time-domain simulations,we found the performance of the self-mixing GaN/AlGaN high electron mobility transistor detector is mainly dependent on the parameters L gs（the gap between the gate and the source/drain antenna） and L w（the gap between the source and drain antenna）.With the improved triple resonant antenna,an optimized micrometer-sized AlGaN/GaN high electron mobility transistor detector can achieve a high responsivity of 9.45×102 V/W at a frequency of 903 GHz at room temperature.

Two-dimensional electron gas characteristics of InP-based high electron mobility transistor terahertz detector

The samples of InxGa（1-x）As/In（0.52）Al（0.48）As two-dimensional electron gas（2DEG）are grown by molecular beam epitaxy（MBE）.In the sample preparation process,the In content and spacer layer thickness are changed and two kinds of methods,i.e.,contrast body doping andδ-doping are used.The samples are analyzed by the Hall measurements at 300 Kand 77 K.The InxGa1-xAs/In0.52Al0.48As 2DEG channel structures with mobilities as high as 10289 cm^2/V·s（300 K）and42040 cm^2/V·s（77 K）are obtained,and the values of carrier concentration（Nc）are 3.465×10^12/cm^2 and 2.502×10^12/cm^2,respectively.The THz response rates of In P-based high electron mobility transistor（HEMT）structures with different gate lengths at 300 K and 77 K temperatures are calculated based on the shallow water wave instability theory.The results provide a reference for the research and preparation of In P-based HEMT THz detectors.

Influence of a two-dimensional electron gas on current-voltage characteristics of Al_(0.3)Ga_(0.7) N/GaN high electron mobility transistors

The J-V characteristics of AltGa1 tN/GaN high electron mobility transistors（HEMTs） are investigated and simulated using the self-consistent solution of the Schro dinger and Poisson equations for a two-dimensional electron gas（2DEG） in a triangular potential well with the Al mole fraction t = 0.3 as an example.Using a simple analytical model,the electronic drift velocity in a 2DEG channel is obtained.It is found that the current density through the 2DEG channel is on the order of 10^13 A/m^2 within a very narrow region（about 5 nm）.For a current density of 7 × 10^13 A/m62 passing through the 2DEG channel with a 2DEG density of above 1.2 × 10^17 m^-2 under a drain voltage Vds = 1.5 V at room temperature,the barrier thickness Lb should be more than 10 nm and the gate bias must be higher than 2 V.

Breakdown voltage analysis of Al_(0.25)Ga_(0.75)N/GaN high electron mobility transistors with partial silicon doping in the AlGaN layer

In this paper,two-dimensional electron gas（2DEG） regions in AlGaN/GaN high electron mobility transistors（HEMTs） are realized by doping partial silicon into the AlGaN layer for the first time.A new electric field peak is introduced along the interface between the AlGaN and GaN buffer by the electric field modulation effect due to partial silicon positive charge.The high electric field near the gate for the complete silicon doping structure is effectively decreased,which makes the surface electric field uniform.The high electric field peak near the drain results from the potential difference between the surface and the depletion regions.Simulated breakdown curves that are the same as the test results are obtained for the first time by introducing an acceptor-like trap into the N-type GaN buffer.The proposed structure with partial silicon doping is better than the structure with complete silicon doping and conventional structures with the electric field plate near the drain.The breakdown voltage is improved from 296 V for the conventional structure to 400 V for the proposed one resulting from the uniform surface electric field.

Electric field driven plasmon dispersion in AlGaN/GaN high electron mobility transistors

We present a theoretical study on the electric field driven plasmon dispersion of the two-dimensional electron gas （2DEG） in A1GaN/GaN high electron mobility transistors （HEMTs）. By introducing a drifted Fermi-Dirac distribution, we calculate the transport properties of the 2DEG in the A1GaN/GaN interface by employing the balance-equation approach based on the Boltzmann equation. Then, the nonequilibrium Fermi-Dirac function is obtained by applying the calculated electron drift velocity and electron temperature. Under random phase approximation （RPA）, the electric field driven plas- mon dispersion is investigated. The calculated results indicate that the plasmon frequency is dominated by both the electric field E and the angle between wavevector q and electric field E. Importantly, the plasmon frequency could be tuned by the applied source-drain bias voltage besides the gate voltage （change of the electron density）.

基于GaAs PHEMT工艺的超宽带多通道开关滤波器组MMIC

基于0.25μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺,研制了一款超宽带7路开关滤波器组单片微波集成电路(MMIC)芯片。芯片内集成了开关、驱动电路和带通滤波器,实现了开关滤波功能。开关采用反射式串-并联混合结构;译码器和驱动电路控制某一支路开关的导通或关断;带通滤波器由集总电感和电容组成。该开关滤波器组芯片通带频率覆盖0.8~18 GHz。探针测试结果表明,开关滤波器组芯片各个支路的中心插入损耗均小于8.5 dB,通带内回波损耗小于10 dB,典型带外衰减大于40 dB。为后续研发尺寸更小、性能更优的开关滤波器组提供了参考。

基于GaAs PHEMT工艺的Ka波段三通道开关滤波器

基于0.15μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺设计了一款22~42 GHz的宽带三通道开关滤波器芯片。该开关滤波器由单刀三掷开关、带通滤波器、控制电路构成。开关采用场效应晶体管(FET)串并结合结构实现。带通滤波器采用梳状结构,一端加载金属-绝缘体-金属(MIM)电容实现。芯片集成了2∶4线译码器作为控制电路,实现通道的选择和切换。芯片尺寸为3.0 mm×2.4 mm×0.1 mm。测试结果表明,三个通道的插入损耗均小于8.5 dB,带内回波损耗均小于-10 dB,带外衰减均大于40 dB。该开关滤波器芯片具有插入损耗小、隔离度高、集成度高、阻带宽的特点。

E波段GaAs PHEMT工艺有源六倍频器MMIC

基于GaAs赝配高电子迁移率晶体管(PHEMT)工艺设计了一款输出频率在E波段的有源六倍频器微波单片集成电路(MMIC)。片上集成六倍频器及输出驱动放大器,采用PHEMT管进行倍频,具有较高输出功率及较小的芯片尺寸。在片探针测试结果显示该倍频器芯片在输入功率5dBm时,输出66~88GHz频率范围内,输出功率大于13dBm,谐波抑制20dBc,功耗600 mW,芯片尺寸为3.0 mm×1.4 mm×0.07 mm。

Growth condition optimization and mobility enhancement through inserting AlAs monolayer in the InP-based In_xGa_(1-x)As/In_(0.52)Al_(0.48)As HEMT structures

The structure of In P-based In_xGa_（1-x） As/In0.52Al0.48 As pseudomorphic high electron mobility transistor（PHEMT）was optimized in detail.Effects of growth temperature,growth interruption time,Si δ-doping condition,channel thickness and In content,and inserted Al As monolayer（ML） on the two-dimensional electron gas（2DEG） performance were investigated carefully.It was found that the use of the inserted Al As monolayer has an enhancement effect on the mobility due to the reduction of interface roughness and the suppression of Si movement.With optimization of the growth parameters,the structures composed of a 10 nm thick In0.75Ga0.25 As channel layer and a 3 nm thick Al As/In0.52Al0.48 As superlattices spacer layer exhibited electron mobilities as high as 12500 cm^2·V-1·s^（-1）（300 K） and 53500 cm^2·V~（-1_·s^（-1）（77 K） and the corresponding sheet carrier concentrations（Ns） of 2.8×10^（12）cm^（-2）and 2.9×1012cm^（-2）,respectively.To the best of the authors＇ knowledge,this is the highest reported room temperature mobility for In P-based HEMTs with a spacer of 3 nm to date.

用于GaN基HEMT栅极金属TiN的ICP刻蚀工艺

GaN基高电子迁移率晶体管(HEMT)在射频(RF)通信及新能源汽车领域有着巨大的应用潜力。TiN材料因其良好的热稳定性、化学稳定性及工艺兼容性,可用作GaN基HEMT的栅极材料。采用ULVAC公司生产的NE-550型电感耦合等离子体(ICP)刻蚀设备对TiN材料进行了干法刻蚀工艺的研究。采用光刻胶作为刻蚀掩膜,Cl_(2)和BCl_(3)混合气体作为工艺气体,通过调整工艺参数,研究了ICP源功率、射频(RF)偏压功率、腔体压力、气体体积流量以及载台温度对TiN刻蚀速率和侧壁角度的影响。最后通过优化工艺参数,得到了TiN刻蚀速率为333 nm/min,底部平整且侧壁角度为81°的栅极结构。

Growth condition optimization and mobility enhancement through prolonging the GaN nuclei coalescence process of AlGaN/AlN/GaN structure

AlGaN/AlN/GaN structures are grown by metalorganic vapor phase epitaxy on sapphire substrates. Influences of AlN interlayer thickness, AlGaN barrier thickness, and Al composition on the two-dimensional electron gas（2DEG） performance are investigated. Lowering the V/III ratio and enhancing the reactor pressure at the initial stage of the hightemperature GaN layer growth will prolong the GaN nuclei coalescence process and effectively improve the crystalline quality and the interface morphology, diminishing the interface roughness scattering and improving 2DEG mobility. AlGaN/AlN/GaN structure with 2DEG sheet density of 1.19 × 10^13cm^-2, electron mobility of 2101 cm^2·V^-1·s^-1, and square resistance of 249 Ω is obtained.

DC～20GHz GaAs PHEMT超宽带低噪声放大器

采用0.15μm GaAs PHEMT工艺,设计了一款DC～20 GHz宽带低噪声放大器,可作为驱动放大器用于光纤通信或作为宽带增益模块用于测试及测量系统中。电路采用分布式放大器结构,单节采用共源共栅的结构形式实现,其与共源结构相比,拥有较低的栅-漏反馈电容和较高的输出并联电阻,使电路具有较宽的频带、较高的增益和较高的线性度等特点。电路采用+8 V电源供电,将芯片及外围器件进行模块化封装后,易于测试和使用。经过实测,带内的典型噪声系数为3 dB,小信号增益达到14 dB,输入回波损耗低于-14 dB,输出回波损耗低于-17 dB,1 dB增益压缩输出功率达到16 dBm。芯片尺寸为3.12 mm×1.574 mm。

9～15 GHz GaAs E-PHEMT高性能线性功率放大器

基于0.15μm GaAs增强型赝配高电子迁移率晶体管(E-PHEMT)工艺,研制了一款用于5G通信和点对点传输的高性能线性功率放大器单片微波集成电路(MMIC)。采用栅宽比为1∶4.4的两级放大结构保证了电路的增益和功率指标满足要求;基于大信号模型实现了最优输入输出阻抗匹配;采用电磁场仿真技术优化设计的MMIC芯片尺寸为2.5 mm×1.1 mm。芯片的在片测试结果表明,静态直流工作点为最大饱和电流的35%、漏压为5 V的条件下,在9~15 GHz频率内,MMIC功率放大器小信号增益大于20 dB,1 dB压缩点输出功率不小于27 dBm,功率附加效率不小于35%,功率回退至19 dBm时三阶交调不大于-37 dBc。

带有小型化Balun的C波段单片GaAs pHEMT单平衡电阻性混频器

本文介绍了一种带有小型化无源Balun的C波段单片GaAs pHEMT单平衡电阻性混频器。Balun采用集总一分布式结构，使其长度与常用2／4耦合线Balun相比缩小了11倍，大大降低了将无源Balun应用于C波段单片集成电路中所需的芯片尺寸。混频器采用单平衡电阻性结构，在零功耗的情况下实现了良好的线性和口间隔离性能。测试结果显示，在固定中频160MHz，本振输入功率0dBm条件下，在3．5～5GI-IzRF频带内，最小变频损耗为8．3dB，1dB压缩点功率为8．0dBm，LO至Ⅲ之问的隔离度为38dB。

一款Ku波段GaAs PHEMT低噪声放大器

面向微波毫米波低噪声放大电路对高性能低噪声放大器件的需求,进行0.15μm栅长GaAs PHEMT低噪声器件制备工艺的开发,在制备工艺中采用了欧姆特性优异的复合帽层欧姆接触、低寄生电容的介质空洞栅结构以及高击穿电压的双槽结构。在此基础上实现了一款性能优异的Ku波段低噪声放大电路,电路在Ku频段全频带(14~18 GHz)内实现了优良的性能,其噪声系数小于1.3 d B,增益大于17 d B。电路采用5 V电源供电,功耗为250 m W,芯片面积为2 mm×1.6 mm;这款性能优异的Ku频段低噪声放大器特别适用于高信噪比要求的卫星通信等应用。

GaAs PHEMT工艺V波段有源二倍频器MMIC

基于标准GaAs赝配高电子迁移率晶体管（PHEMT）工艺,设计了一个输出频率在V波段的有源二倍频器单片微波集成电路（MMIC）,实现了高输出功率和良好的谐波抑制特性。芯片内部集成了180°马逊巴伦、对管变频和输出功率放大器等电路。重点优化设计了马逊巴伦的版图结构,在宽带内具有良好的相位和幅度特性;分析了对管变频结构电路的原理,确定其最佳工作电压在压断电压附近;设计了V波段两级放大器电路,对带内信号放大的同时抑制了带外谐波信号,提高了整个倍频器的输出功率。芯片采用微波探针台在片测试,在外加3.5 V电源电压下的工作电流为147 mA;输入功率为14 dBm时,在55-65 GHz输出带宽内的输出功率为13 dBm;带内基波抑制大于20 dBc,芯片面积为2.1 mm×1.3 mm。此倍频器MMIC可应用于V波段通信系统和微波测量系统。

一款GaAs PHEMT超宽带无源双平衡混频器MMIC

混频器是微波系统关键部件之一。微波通信系统的宽带化和小型化发展趋势对混频器性能提出更高要求。基于GaAs赝配高电子迁移率晶体管(PHEMT)工艺设计了一款超宽带无源双平衡混频器单片微波集成电路(MMIC)。该混频器采用环形肖特基二极管结构和两个新颖的螺旋式平行耦合微带线巴伦结构,大大提高了混频器工作带宽,减小了芯片尺寸,提高了本振(LO)到射频(RF)端口的隔离度。在片探针测试结果显示该芯片在上、下变频模式下RF和LO工作频率均为2~22 GHz,中频工作频率为0~4 GHz,变频损耗≤11.5 dB,LO到RF端口隔离度≥37 dB,LO输入功率为15 dBm。芯片尺寸为1.7 mm×1.0 mm。

0.15μm Y型栅高In沟道GaAs PHEMT低噪声器件设计

设计了一种GaAs PHEMT低噪声器件。通过电子束直写手段实现了0.15μm Y型栅,对栅型优化以减小器件栅电阻和栅寄生电容。采用高In含量的沟道设计以改善沟道电子输运特性,采用InGaAs/GaAs复合帽层以改善欧姆接触特性,并通过低噪声工艺流程制作了4×50μm GaAs PHEMT器件。测试结果表明,器件fT达到80GHz,在10GHz处最小噪声系数小于0.4dB,相关增益大于10dB。对于0.15μm栅长GaAs PHEMT器件来说,这是很好的结果。