高跨导AlGaN/GaN HEMT器件

报道了生长在蓝宝石衬底上的AlGaN/GaN HEMT器件的制造工艺以及在室温下器件的性能.器件的栅长为1.0μm,源漏间距为4.0μm.器件的最大电流密度达到1000mA/mm,最大跨导高达198mS/mm,转移特性曲线表现出增益带宽较宽的特点.同时由所测得的S参数推出栅长为1.0μm器件的截止频率(fT)和最高振荡频率(fmax)分别为18.7GHz和19.1GHz.     

高跨导AlGaN/GaN HEMT器件

报道了生长在蓝宝石衬底上的AlGaN/GaNHEMT器件的制造工艺以及在室温下器件的性能.器件的栅长为1 0 μm ,源漏间距为4 0 μm .器件的最大电流密度达到1 0 0 0mA/mm ,最大跨导高达1 98mS/mm ,转移特性曲线表现出增益带宽较宽的特点.同时由所测得的S参数推出栅长为1 0 μm器件的截止频率(fT)和最高振荡频率(fmax)分别为1 8 7GHz和1 9 1GHz.     

InGaN背势垒AlGaN/GaN HEMT中的电流崩塌研究

Current collapses were studied,which were observed in AlGaN/GaN high electron mobility transistors(HEMTs) with and without InGaN back barrier(BB) as a result of short-term bias stress.More serious drain current collapses were observed in InGaN BB AlGaN/GaN HEMTs compared with the traditional HEMTs.The results indicate that the defects and surface states induced by the InGaN BB layer may enhance the current collapse.The surface states may be the primary mechanism of the origination of current collapse in AlGaN/GaN HEMTs for short-term direct current stress.     

AlGaN/GaN HEMT器件的研制

介绍了AlGaN/GaN HEMT器件的研制及室温下器件特性的测试.漏源欧姆接触采用Ti/Al/Pt/Au,肖特基结金属为Pt/Au.器件栅长为1μm,获得的最大跨导为120mS/mm,最大的漏源饱和电流密度为0.95A/mm.     

AlGaN/GaN HEMT器件的研制

介绍了AlGaN/GaNHEMT器件的研制及室温下器件特性的测试.漏源欧姆接触采用Ti/Al/Pt/Au ,肖特基结金属为Pt/Au .器件栅长为1μm ,获得的最大跨导为12 0mS/mm ,最大的漏源饱和电流密度为0 95A/mm .     

AlGaN/GaN共栅共源HEMTs器件

研究了蓝宝石衬底AlGaN／GaN共栅共源器件的特性。该器件包括栅长0．8μm共源器件与栅长1μm的共栅器件。研究表明,共栅共源器件的第二栅压对的器件饱和电流与跨导有明显的调制作用,容易实现功率增益控制。与共源器件相比,共栅共源器件在微波特性上fT大约9GHz,比共源器件稍小,但是具有较低的反馈,显著增加的功率资用增益及较高的端口阻抗,与共源器件相比,稳定性更好,可以避免振荡的产生,结合GaN的高功率特性GaN共栅共源器件非常适合微波频段宽频大功率领域的应用。     

增强型AlGaN/GaN槽栅HEMT

成功研制出蓝宝石衬底的槽栅增强型AlGaN/GaN HEMT. 栅长1.2μm,源漏间距4μm,槽深15nm的器件在3V栅压下饱和电流达到332mA/mm,最大跨导为221mS/mm,阈值电压为0.57V, ft和fmax分别为5.2和9.3GHz. 比较刻蚀前后的肖特基I-V特性,证实了槽栅刻蚀过程中非有意淀积介质层的存在. 深入研究了增强型器件亚阈特性和频率特性.     

增强型AlGaN/GaN槽栅HEMT

成功研制出蓝宝石衬底的槽栅增强型AlGaN/GaN HEMT.栅长1.2μm.源漏间距4μm,槽深15nm的器件在3V栅压下饱和电流达到332mA/mm,最大跨导为221mS/mm,阈值电压为0.57V,ft和,fmax分别为5.2和9.3GHz.比较刎蚀前后的肖特基,Ⅰ-Ⅴ特性,证实了槽栅刻蚀过程中非有意淀积介质层的存在.深入研究了增强型器件亚阈特性和频率特性.     

AlGaN/GaN HEMT凹栅槽结构器件的频率特性

采用一系列不同栅长和结构的T型栅器件来研究凹栅槽结构抑制短沟道效应和提高频率特性的作用.随着栅长不断缩短,短沟道效应逐渐明显,栅长从300 nm缩短至100 nm时,亚阈值摆幅逐渐增大,栅对沟道载流子的控制变弱,且器件出现软夹断现象.凹栅槽结构可以降低器件的亚阈值接幅,提高开关比,栅长100 nm常规结构器件的亚阈值摆幅为140 mV/dec,开关比为106,而凹栅槽结构器件的亚阈值摆幅下降为95 mV/dec,开关比增大为107,凹栅槽结构明显抑制了短沟道效应.在漏源电压为20 V时,100 nm栅长的凹栅槽结构器件的截止频率和最高振荡频率达到了65.9和191 GHz,同常规结构相比,分别提高了5.78％和4.49％.由于凹栅槽结构缩短了栅金属到二维电子气(2DEG)沟道的间距,增大了纵横比,所以能够改善器件的频率特性.     

栅脉冲下AlGaN/GaN HEMT电流崩塌效应研究

源于AlGaN/GaNHEMT器件的大量测试分析发现,栅脉冲条件下漏极电流比直流情况下减小了47%;随着信号频率的改变,漏极电流按μnCoxW[α (0.13 0.64f)VGS (0.13 0.32 f)VGS2](VGS-Vth)2/L的规律变化;脉冲信号宽度对漏电流崩塌影响较小.基于实验结果的理论分析认为,电子从栅极注入到栅漏之间并被表面态所俘获,在沟道中形成增加的耗尽层,使得沟道二维电子气浓度减小,从而导致形成电流崩塌效应的主要原因之一.该结论有助于AlGaN HEMT器件脉冲条件下电流崩塌效应理论解释和器件应用.     

X波段AlGaN/GaN HEMTs Γ栅场板结构研究

基于SiC衬底成功研制X波段0.25 μm栅长带有r栅场板结构的AlGaN/GaN HEMT,设计场板(field plate)长度为0.4 μm,0.6μm,0.7μm,0.9μm.研究了r栅场板长度及不同漏偏压下对器件直流,小信号特性及大信号的影响.器件直流I-V及转移特性并不依赖场板长度变化,增加场板长度器件击穿电压提高可达108 V,器件截止频率及振荡频率下降,输出功率大幅度提高,结合器件小信号提参结果分析.8 GHz下,总栅宽1 mm,场板长度为0.9 μm的器件,连续波输出功率密度7.11 W/mm,功率附加效率(PAE)35.31%,相应线性增益10.25 dB.     

采用注入隔离制造的AlGaN/GaN HEMTs器件

对Al Ga N/Ga N HEMT器件采用离子注入技术注入氦离子进行隔离,应用该技术制造出的器件在室温下具有很好的特性.器件的阈值电压在- 3V左右时,源漏间电流为几十n A.肖特基势垒的反向漏电流在- 1 0 V下约为几百n A.与采用干法刻蚀技术进行隔离的器件相比,采用离子注入技术不但可以获得全平面化的HEMTs器件而且还有效地抑制了场区漏电.研究还表明氦离子注入的温度稳定性大于70 0℃.     

AlGaN/GaN HEMT欧姆接触的研究进展

从欧姆接触形成的机理出发,介绍了在AlGaN/GaN HEMT中实现源和漏区欧姆接触的各种方法,如表面处理技术、金属化系统和重掺杂技术等.回顾了近年来这些方法的研究进展.     

Effect of the post-gate annealing on the gate reliability of AlGaN/GaN HEMTs

In this paper,we investigated the effect of post-gate annealing (PGA) on reverse gate leakage and the reverse bias reli-ability of Al0.23Ga0.77N/GaN high electron mobility transistors (HEMTs).We found that the Poole-Frenkel (PF) emission is domin-ant in the reverse gate leakage current at the low reverse bias region (Vth ＜ VG ＜ 0 V) for the unannealed and annealed HEMTs.The emission barrier height of HEMT is increased from 0.139 to 0.256 eV after the PGA process,which results in a reduction of the reverse leakage current by more than one order.Besides,the reverse step stress was conducted to study the gate reliabil-ity of both HEMTs.After the stress,the unannealed HEMT shows a higher reverse leakage current due to the permanent dam-age of the Schottky gate.In contrast,the annealed HEMT shows a little change in reverse leakage current.This indicates that the PGA can reduce the reverse gate leakage and improve the gate reliability.     

UV/Ozone 表面处理对AlGaN/GaN HEMTs 性能的影响

工艺过程中对晶圆表面处理对制作出高性能的AlGaN/GaN HEMT起到至关重要的作用,洁净的表面能够有效提高器件性能以及器件可靠性。本文发现通过UV/Ozone表面处理,AlGaN/GaN HEMT器件的欧姆接触以及肖特基接触的电学特性均发生明显变化,根据实验中现象以及相关实验数据,并且采用X射线光电子能谱对实验样品进行表面分析测试,着重阐述了UV/Ozone处理对晶圆表面的作用,以及其影响AlGaN/GaN HEMT器件欧姆接触特性以及肖特基接触特性的原因。     

X波段AlGaN/GaN HEMTs厂栅场板结构研究

基于SiC衬底成功研制X波段0.25um栅长带有г栅场板结构的AlGaN/GaN HEMT,对比T型栅结构器件,研究了г栅场板引入对器件直流、小信号及微波功率特性的影响.结果表明,г栅场板结构减小器件截止频率及振荡频率,但明显改善器件膝点电压和输出功率密度.针对场板长度分别为0.4、0.7、0.9、1.1 um,得出一定范围内增加场板长度,器件输出功率大幅度提高,并结合器件小信号模型提参结果分析原因.在频率8 GHz下,总栅宽1 mm,场板长度0.9um的器件,连续波输出功率密度7.11 W/mm,功率附加效率(PAE)35.31%,相应线性增益10.25 dB.     

Off-state breakdown and leakage current transport analysis of AlGaN/GaN high electron mobility transistors

Off-state breakdown characteristics of AlGaN/GaN high-electron-mobility transistors have been studied based on drain current injection method. It is found that at low drain current injection level, the observed premature breakdown is caused by excess gate-to-drain leakage current. Nevertheless, at high drain injection current level, buffer-leakage-dominated breakdown proceeds gate-leakage-dominated breakdown as the gate bias increases from pinch-off voltage to deep-depletion voltage. In both breakdown regions, the breakdown voltages show negative temperature coefficients. The buffer-leakage-induced breakdown should be defect-related, which is confirmed by temperature-dependent buffer leakage measurements.     

一种氮化镓高迁移率晶体管的栅电流噪声模型

This work presents a theoretical and experimental study on the gate current 1/f noise in Al Ga N/Ga N HEMTs. Based on the carrier number fluctuation in the two-dimensional electron gas channel of Al Ga N/Ga N HEMTs, a gate current 1/f noise model containing a trap-assisted tunneling current and a space charge limited current is built. The simulation results are in good agreement with the experiment. Experiments show that, if Vg Vx, gate current 1/f noise comes from not only the trap-assisted tunneling RTS, but also the space charge limited current RTS. This indicates that the gate current 1/f noise of the Ga N-based HEMTs device is sensitive to the interaction of defects and the piezoelectric relaxation. It provides a useful characterization tool for deeper information about the defects and their evolution in Al Ga N/Ga N HEMTs.     

蓝宝石衬底AlGaN/GaN共栅共源微波HEMTs器件

报道了蓝宝石衬底AlGaN/GaN共栅共源器件的制备与特性.该器件包括栅长为0.8μm共源器件与栅长为1μm的共栅器件.实验表明,共栅器件的第二栅压会显著影响器件饱和电流与跨导特性,从而控制功率增益.与共源器件相比,共栅共源器件表现出稍低的 f T、较低的反馈、显著增加的功率资用增益及较高的端口阻抗.