Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electro...Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron gas(2DEG)channel.The fabricated E-mode HEMTs exhibit a relatively high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact.展开更多
In this letter,high power density AlGaN/GaN high electron-mobility transistors(HEMTs)on a freestanding GaN substrate are reported.An asymmetricΓ-shaped 500-nm gate with a field plate of 650 nm is introduced to improv...In this letter,high power density AlGaN/GaN high electron-mobility transistors(HEMTs)on a freestanding GaN substrate are reported.An asymmetricΓ-shaped 500-nm gate with a field plate of 650 nm is introduced to improve microwave power performance.The breakdown voltage(BV)is increased to more than 200 V for the fabricated device with gate-to-source and gate-to-drain distances of 1.08 and 2.92μm.A record continuous-wave power density of 11.2 W/mm@10 GHz is realized with a drain bias of 70 V.The maximum oscillation frequency(f_(max))and unity current gain cut-off frequency(f_(t))of the AlGaN/GaN HEMTs exceed 30 and 20 GHz,respectively.The results demonstrate the potential of AlGaN/GaN HEMTs on freestanding GaN substrates for microwave power applications.展开更多
以定制硅(Si)、蓝宝石(Al2O3)和碳化硅(SiC)衬底的AlGaN/GaN高电子迁移率晶体管(high electron mobility transistors,HEMTs)为研究对象,在CFBR-II(China Fast Burst Reactor-II)快中子脉冲堆开展了中子辐照注量范围为10^(13)~10^(15) c...以定制硅(Si)、蓝宝石(Al2O3)和碳化硅(SiC)衬底的AlGaN/GaN高电子迁移率晶体管(high electron mobility transistors,HEMTs)为研究对象,在CFBR-II(China Fast Burst Reactor-II)快中子脉冲堆开展了中子辐照注量范围为10^(13)~10^(15) cm^(-2)的辐照实验研究;运用Sentaurus TCAD软件对Si衬底HEMTs器件开展了数值模拟仿真。结果表明:HEMTs器件的I-V等特性的变化,随着中子辐照注量的增大,并未如预期呈现出单调的线性递减趋势;对于Si衬底的定制器件,在小于10^(15) cm^(-2)的辐照注量下,甚至出现了饱和漏电流增加现象。分析认为,辐照产生的施主型陷阱与受主型陷阱之间的竞争补偿作用过程,是导致实验现象出现的主要物理机制;与原生缺陷相关的施主型陷阱的产生和注量率效应,可用来解释实验观测到的反常增加趋势。基于不同种类陷阱对器件作用机制的定量分析,定位GaN缓冲层为器件的薄弱环节并提出了加固建议,推断器件性能会在注量为10^(15)~10^(16) cm^(-2)时出现显著退化及失效,并尝试开展多轮次搭载实验进行验证。展开更多
The reverse gate leakage mechanism of W-gate and Ti N-gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with N2plasma surface treatment is investigated using current–voltage(I–V)and capacitance–voltage(C–V)c...The reverse gate leakage mechanism of W-gate and Ti N-gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with N2plasma surface treatment is investigated using current–voltage(I–V)and capacitance–voltage(C–V)characteristics and theoretical calculation analysis.It is found that the main reverse gate leakage mechanism of both devices is the trapassisted tunneling(TAT)mechanism in the entire reverse bias region(-30 V to 0 V).It is also found that the reverse gate leakage current of the W-gate Al GaN/GaN HEMTs is smaller than that of the TiN gate at high reverse gate bias voltage.Moreover,the activation energies of the extracted W-gate and Ti N-gate AlGaN/GaN HEMTs are 0.0551 e V–0.127 eV and0.112 eV–0.201 eV,respectively.展开更多
Dynamic characteristics of the single-crystal Ga N-passivated lateral AlGaN/GaN Schottky barrier diodes(SBDs)treated with proton irradiation are investigated.Radiation-induced changes including idealized Schottky inte...Dynamic characteristics of the single-crystal Ga N-passivated lateral AlGaN/GaN Schottky barrier diodes(SBDs)treated with proton irradiation are investigated.Radiation-induced changes including idealized Schottky interface and slightly degraded on-resistance(RON)are observed under 10-Me V proton irradiation at a fluence of 10^(14)cm^(-2).Because of the existing negative polarization charges induced at GaN/AlGaN interface,the dynamic ON-resistance(RON,dyn)shows negligible degradation after a 1000-s-long forward current stress of 50 mA to devices with and without being irradiated by protons.Furthermore,the normalized RON,dynincreases by only 14%that of the initial case after a 100-s-long bias of-600 V has been applied to the irradiated devices.The high-performance lateral AlGaN/GaN SBDs with tungsten as anode metal and in-situ single-crystal GaN as passivation layer show a great potential application in the harsh radiation environment of space.展开更多
基金supported in part by the National Key Research and Development Program of China under Grant 2022YFB3604400in part by the Youth Innovation Promotion Association of Chinese Academy Sciences(CAS)+4 种基金in part by CAS-Croucher Funding Scheme under Grant CAS22801in part by National Natural Science Foundation of China under Grant 62074161,Grant 62004213,and Grant U20A20208in part by the Beijing Municipal Science and Technology Commission project under Grant Z201100008420009 and Grant Z211100007921018in part by the University of CASin part by IMECAS-HKUST-Joint Laboratory of Microelectronics.
文摘Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron gas(2DEG)channel.The fabricated E-mode HEMTs exhibit a relatively high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact.
文摘In this letter,high power density AlGaN/GaN high electron-mobility transistors(HEMTs)on a freestanding GaN substrate are reported.An asymmetricΓ-shaped 500-nm gate with a field plate of 650 nm is introduced to improve microwave power performance.The breakdown voltage(BV)is increased to more than 200 V for the fabricated device with gate-to-source and gate-to-drain distances of 1.08 and 2.92μm.A record continuous-wave power density of 11.2 W/mm@10 GHz is realized with a drain bias of 70 V.The maximum oscillation frequency(f_(max))and unity current gain cut-off frequency(f_(t))of the AlGaN/GaN HEMTs exceed 30 and 20 GHz,respectively.The results demonstrate the potential of AlGaN/GaN HEMTs on freestanding GaN substrates for microwave power applications.
文摘The reverse gate leakage mechanism of W-gate and Ti N-gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with N2plasma surface treatment is investigated using current–voltage(I–V)and capacitance–voltage(C–V)characteristics and theoretical calculation analysis.It is found that the main reverse gate leakage mechanism of both devices is the trapassisted tunneling(TAT)mechanism in the entire reverse bias region(-30 V to 0 V).It is also found that the reverse gate leakage current of the W-gate Al GaN/GaN HEMTs is smaller than that of the TiN gate at high reverse gate bias voltage.Moreover,the activation energies of the extracted W-gate and Ti N-gate AlGaN/GaN HEMTs are 0.0551 e V–0.127 eV and0.112 eV–0.201 eV,respectively.
基金Project supported by the National Natural Science Foundation of China(Grant No.62104185)the Fundamental Research Funds for the Central Universities,China(Grant No.JB211103)+1 种基金the National Natural Science Foundation for Distinguished Young Scholars,China(Grant No.61925404)the Wuhu and Xidian University Special Fund for Industry–University-Research Cooperation,China(Grant No.XWYCXY-012021010)。
文摘Dynamic characteristics of the single-crystal Ga N-passivated lateral AlGaN/GaN Schottky barrier diodes(SBDs)treated with proton irradiation are investigated.Radiation-induced changes including idealized Schottky interface and slightly degraded on-resistance(RON)are observed under 10-Me V proton irradiation at a fluence of 10^(14)cm^(-2).Because of the existing negative polarization charges induced at GaN/AlGaN interface,the dynamic ON-resistance(RON,dyn)shows negligible degradation after a 1000-s-long forward current stress of 50 mA to devices with and without being irradiated by protons.Furthermore,the normalized RON,dynincreases by only 14%that of the initial case after a 100-s-long bias of-600 V has been applied to the irradiated devices.The high-performance lateral AlGaN/GaN SBDs with tungsten as anode metal and in-situ single-crystal GaN as passivation layer show a great potential application in the harsh radiation environment of space.
文摘本文对金属有机物化学气相淀积法在4英寸GaN衬底上生长出的高质量AlGaN/GaN HEMT外延材料进行了研究分析。生长过程采用NH_(3)/H_(2)混合气体及H_(2)交替通入的方法对衬底表面进行了预处理,阻隔了界面杂质的扩散。得益于衬底与外延的高度晶格匹配,GaN材料的螺位错密度降低到1.4×10^(7)cm^(-2),刃位错密度降低到3.0×10^(6)cm^(-2);非接触霍尔测试仪结果显示二维电子气迁移率为2159 cm^(2)/V·s,说明制备的材料晶体质量高且电学性能优异。此外,由于衬底与外延之间不存在热失配,使用拉曼光谱仪发现同质外延的Ga N E2(TO)峰位与衬底的E2(TO)峰位完全重合,表明同质外延过程中无应力应变产生。
