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
A power amplifier MIC with power combining based on AlGaN/GaN HEMTs was fabricated and measured. The amplifier consists of four 10 × 120μm transistors. A Wilkinson splitters and combining were used to divide and...A power amplifier MIC with power combining based on AlGaN/GaN HEMTs was fabricated and measured. The amplifier consists of four 10 × 120μm transistors. A Wilkinson splitters and combining were used to divide and combine the power. By biasing the amplifier at VDS = 40V, IDS = 0.9A, a maximum CW output power of 41.4dBm with a maximum power added efficiency （PAE） of 32.54% and a power combine efficiency of 69% was achieved at 5.4GHz.展开更多
比较了空气桥跨细栅和空气桥跨栅总线两种源连接结构的1 mm AlGaN/GaN HEMTs器件的特性,对两种结构的管芯进行了等效电路参数提取。测试了两种布局方式下的不同源场板结构器件的射频以及功率性能,比较分析表明,空气桥跨细栅的源连接方...比较了空气桥跨细栅和空气桥跨栅总线两种源连接结构的1 mm AlGaN/GaN HEMTs器件的特性,对两种结构的管芯进行了等效电路参数提取。测试了两种布局方式下的不同源场板结构器件的射频以及功率性能,比较分析表明,空气桥跨细栅的源连接方式由于有效地降低了栅漏电容以及栅源电容,比空气桥跨栅总线源连接的器件能取得更好的频率特性以及功率特性。展开更多
High-performance low-leakage-current A1GaN/GaN high electron mobility transistors （HEMTs） on silicon （111） sub- strates grown by metal organic chemical vapor deposition （MOCVD） with a novel partially Magnesium ...High-performance low-leakage-current A1GaN/GaN high electron mobility transistors （HEMTs） on silicon （111） sub- strates grown by metal organic chemical vapor deposition （MOCVD） with a novel partially Magnesium （Mg）-doped GaN buffer scheme have been fabricated successfully. The growth and DC results were compared between Mg-doped GaN buffer layer and a unintentionally onμe. A 1μ m gate-length transistor with Mg-doped buffer layer exhibited an OFF-state drain leakage current of 8.3 × 10-8 A/mm, to our best knowledge, which is the lowest value reported for MOCVD-grown A1GaN/GaN HEMTs on Si featuring the same dimension and structure. The RF characteristics of 0.25-μ m gate length T-shaped gate HEMTs were also investigated.展开更多
In this paper,we investigated the effect of post-gate annealing(PGA)on reverse gate leakage and the reverse bias reliability of Al_(0.23)Ga_(0.77)N/GaN high electron mobility transistors(HEMTs).We found that the Poole...In this paper,we investigated the effect of post-gate annealing(PGA)on reverse gate leakage and the reverse bias reliability of Al_(0.23)Ga_(0.77)N/GaN high electron mobility transistors(HEMTs).We found that the Poole-Frenkel(PF)emission is dominant in the reverse gate leakage current at the low reverse bias region(V_(th)<V_(G)<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 reliability of both HEMTs.After the stress,the unannealed HEMT shows a higher reverse leakage current due to the permanent damage 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.展开更多
Although outstanding microwave power performance of AlGaN/GaN HEMTs has been reported,drain current collapse is still a problem. In this paper,an experiment was carried out to demonstrate one factor causing the collap...Although outstanding microwave power performance of AlGaN/GaN HEMTs has been reported,drain current collapse is still a problem. In this paper,an experiment was carried out to demonstrate one factor causing the collapse. Two AlGaN/GaN samples were annealed under N2-atmosphere with and without carbon incorporation, and the XPS measurement technique was used to determine that the concentration of carbon impurity in the latter sample was far higher than in the former. From the comparison of two Id- Vds characteristics,we conclude that carbon impurity incorporation is responsible for the severe current collapse. The carbon impurity-induced deep traps under negative gate bias stress can capture the channel carriers, which release slowly from these traps under positive bias stress,thus causing the current collapse.展开更多
AlGaN/GaN high electron mobility transistor (HEMT) materials are grown by RF plasma-assisted molecular beam epitaxy (RF-MBE) and HEMT devices are fabricated and characterized.The HEMT materials have a mobility of 1035...AlGaN/GaN high electron mobility transistor (HEMT) materials are grown by RF plasma-assisted molecular beam epitaxy (RF-MBE) and HEMT devices are fabricated and characterized.The HEMT materials have a mobility of 1035cm2/(V·s) at sheet electron concentration of 1.0×10 13cm -2at room temperature.For the devices fabricated using the materials,a maximum saturation drain-current density of 925mA/mm and a peak extrinsic transconductance of 186mS/mm are obtained on devices with gate length and width of 1μm and 80μm respectively.The f t,unit-current-gain frequency of the devices,is about 18.8GHz.展开更多
We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors(HEMTs)with thin-barrier to minimize surface leakage current to enhance the breakdown voltage.The bilay...We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors(HEMTs)with thin-barrier to minimize surface leakage current to enhance the breakdown voltage.The bilayer SiN with 20-nm Si-rich SiN and 100-nm Si_(3)N_(4) was deposited by plasma-enhanced chemical vapor deposition(PECVD)after removing 20-nm SiO_(2)pre-deposition layer.Compared to traditional Si_(3)N_(4) passivation for thin-barrier AlGaN/GaN HEMTs,Si-rich SiN bilayer passivation can suppress the current collapse ratio from 18.54%to 8.40%.However,Si-rich bilayer passivation leads to a severer surface leakage current,so that it has a low breakdown voltage.The 20-nm SiO_(2)pre-deposition layer can protect the surface of HEMTs in fabrication process and decrease Ga–O bonds,resulting in a lower surface leakage current.In contrast to passivating Si-rich SiN directly,devices with the novel Si-rich SiN bilayer passivation increase the breakdown voltage from 29 V to 85 V.Radio frequency(RF)small-signal characteristics show that HEMTs with the novel bilayer SiN passivation leads to f_(T)/f_(max) of 68 GHz/102 GHz.At 30 GHz and V_(DS)=20 V,devices achieve a maximum P_(out) of 5.2 W/mm and a peak power-added efficiency(PAE)of 42.2%.These results indicate that HEMTs with the novel bilayer SiN passivation can have potential applications in the millimeter-wave range.展开更多
The behavior of Schottky contacts in AlGaN/GaN high electron mobility transistors （HEMTs） is investigated by temperature-dependent current-voltage （T-I-V） measurements from 300 K to 473 K. The ideality factor and ...The behavior of Schottky contacts in AlGaN/GaN high electron mobility transistors （HEMTs） is investigated by temperature-dependent current-voltage （T-I-V） measurements from 300 K to 473 K. The ideality factor and barrier height determined based on the thermionic emission （TE） theory are found to be strong functions of temperature, while present a great deviation from the theoretical value, which can be expounded by the barrier height inhomogeneities. In order to determine the forward current transport mechanisms, the experimental data are analyzed using numerical fitting method, considering the temperature-dependent series resistance. It is observed that the current flow at room temperature can be attributed to the tunneling mechanism, while thermionic emission current gains a growing proportion with an increase in temperature. Finally, the effective barrier height is derived based on the extracted thermionic emission component, and an evaluation of the density of dislocations is made from the I-V characteristics, giving a value of 1.49 × 10^7 cm^-2.展开更多
An atomic-level controlled etching(ACE)technology is invstigated for the fabrication of recessed gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with high power added efficiency.We compare the recessed gate HE...An atomic-level controlled etching(ACE)technology is invstigated for the fabrication of recessed gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with high power added efficiency.We compare the recessed gate HEMTs with conventional etching(CE)based chlorine,Cl_(2)-only ACE and BCl^(3)/Cl_(2)ACE,respectively.The mixed radicals of BCl_(3)/Cl_(2)were used as the active reactants in the step of chemical modification.For ensuring precise and controllable etching depth and low etching damage,the kinetic energy of argon ions was accurately controlled.These argon ions were used precisely to remove the chemical modified surface atomic layer.Compared to the HEMTs with CE,the characteristics of devices fabricated by ACE are significantly improved,which benefits from significant reduction of etching damage.For BCl_(3)/Cl_(2)ACE recessed HEMTs,the load pull test at 17 GHz shows a high power added efficiency(PAE)of 59.8%with an output power density of 1.6 W/mm at Vd=10 V,and a peak PAE of 44.8%with an output power density of 3.2 W/mm at Vd=20 V in a continuous-wave mode.展开更多
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...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℃ .展开更多
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.
文摘A power amplifier MIC with power combining based on AlGaN/GaN HEMTs was fabricated and measured. The amplifier consists of four 10 × 120μm transistors. A Wilkinson splitters and combining were used to divide and combine the power. By biasing the amplifier at VDS = 40V, IDS = 0.9A, a maximum CW output power of 41.4dBm with a maximum power added efficiency （PAE） of 32.54% and a power combine efficiency of 69% was achieved at 5.4GHz.
文摘比较了空气桥跨细栅和空气桥跨栅总线两种源连接结构的1 mm AlGaN/GaN HEMTs器件的特性,对两种结构的管芯进行了等效电路参数提取。测试了两种布局方式下的不同源场板结构器件的射频以及功率性能,比较分析表明,空气桥跨细栅的源连接方式由于有效地降低了栅漏电容以及栅源电容,比空气桥跨栅总线源连接的器件能取得更好的频率特性以及功率特性。
文摘High-performance low-leakage-current A1GaN/GaN high electron mobility transistors （HEMTs） on silicon （111） sub- strates grown by metal organic chemical vapor deposition （MOCVD） with a novel partially Magnesium （Mg）-doped GaN buffer scheme have been fabricated successfully. The growth and DC results were compared between Mg-doped GaN buffer layer and a unintentionally onμe. A 1μ m gate-length transistor with Mg-doped buffer layer exhibited an OFF-state drain leakage current of 8.3 × 10-8 A/mm, to our best knowledge, which is the lowest value reported for MOCVD-grown A1GaN/GaN HEMTs on Si featuring the same dimension and structure. The RF characteristics of 0.25-μ m gate length T-shaped gate HEMTs were also investigated.
基金supported by the National Key Research and Development Program of China(2017YFB0402900)the National Natural Sciences Foundation of China(62074144).
文摘In this paper,we investigated the effect of post-gate annealing(PGA)on reverse gate leakage and the reverse bias reliability of Al_(0.23)Ga_(0.77)N/GaN high electron mobility transistors(HEMTs).We found that the Poole-Frenkel(PF)emission is dominant in the reverse gate leakage current at the low reverse bias region(V_(th)<V_(G)<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 reliability of both HEMTs.After the stress,the unannealed HEMT shows a higher reverse leakage current due to the permanent damage 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.
文摘Although outstanding microwave power performance of AlGaN/GaN HEMTs has been reported,drain current collapse is still a problem. In this paper,an experiment was carried out to demonstrate one factor causing the collapse. Two AlGaN/GaN samples were annealed under N2-atmosphere with and without carbon incorporation, and the XPS measurement technique was used to determine that the concentration of carbon impurity in the latter sample was far higher than in the former. From the comparison of two Id- Vds characteristics,we conclude that carbon impurity incorporation is responsible for the severe current collapse. The carbon impurity-induced deep traps under negative gate bias stress can capture the channel carriers, which release slowly from these traps under positive bias stress,thus causing the current collapse.
文摘AlGaN/GaN high electron mobility transistor (HEMT) materials are grown by RF plasma-assisted molecular beam epitaxy (RF-MBE) and HEMT devices are fabricated and characterized.The HEMT materials have a mobility of 1035cm2/(V·s) at sheet electron concentration of 1.0×10 13cm -2at room temperature.For the devices fabricated using the materials,a maximum saturation drain-current density of 925mA/mm and a peak extrinsic transconductance of 186mS/mm are obtained on devices with gate length and width of 1μm and 80μm respectively.The f t,unit-current-gain frequency of the devices,is about 18.8GHz.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFB1804902)the National Natural Science Foundation of China(Grant Nos.61904135,62090014,and 11690042)+4 种基金the Fundamental Research Funds for the Central Universities,the Innovation Fund of Xidian University(Grant No.YJS2213)the China Postdoctoral Science Foundation(Grant Nos.2018M640957 and BX20200262)the Key Research and Development Program of Guangzhou(Grant No.202103020002)Wuhu and Xidian University Special Fund for Industry–University-Research Cooperation(Grant No.XWYCXY-012021014HT)the Fundamental Research Funds for the Central Universities,China(Grant No.XJS221110)。
文摘We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors(HEMTs)with thin-barrier to minimize surface leakage current to enhance the breakdown voltage.The bilayer SiN with 20-nm Si-rich SiN and 100-nm Si_(3)N_(4) was deposited by plasma-enhanced chemical vapor deposition(PECVD)after removing 20-nm SiO_(2)pre-deposition layer.Compared to traditional Si_(3)N_(4) passivation for thin-barrier AlGaN/GaN HEMTs,Si-rich SiN bilayer passivation can suppress the current collapse ratio from 18.54%to 8.40%.However,Si-rich bilayer passivation leads to a severer surface leakage current,so that it has a low breakdown voltage.The 20-nm SiO_(2)pre-deposition layer can protect the surface of HEMTs in fabrication process and decrease Ga–O bonds,resulting in a lower surface leakage current.In contrast to passivating Si-rich SiN directly,devices with the novel Si-rich SiN bilayer passivation increase the breakdown voltage from 29 V to 85 V.Radio frequency(RF)small-signal characteristics show that HEMTs with the novel bilayer SiN passivation leads to f_(T)/f_(max) of 68 GHz/102 GHz.At 30 GHz and V_(DS)=20 V,devices achieve a maximum P_(out) of 5.2 W/mm and a peak power-added efficiency(PAE)of 42.2%.These results indicate that HEMTs with the novel bilayer SiN passivation can have potential applications in the millimeter-wave range.
基金supported by the National Natural Science Foundation of China(Grant No.61334002)the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory of China(Grant No.ZHD201206)
文摘The behavior of Schottky contacts in AlGaN/GaN high electron mobility transistors （HEMTs） is investigated by temperature-dependent current-voltage （T-I-V） measurements from 300 K to 473 K. The ideality factor and barrier height determined based on the thermionic emission （TE） theory are found to be strong functions of temperature, while present a great deviation from the theoretical value, which can be expounded by the barrier height inhomogeneities. In order to determine the forward current transport mechanisms, the experimental data are analyzed using numerical fitting method, considering the temperature-dependent series resistance. It is observed that the current flow at room temperature can be attributed to the tunneling mechanism, while thermionic emission current gains a growing proportion with an increase in temperature. Finally, the effective barrier height is derived based on the extracted thermionic emission component, and an evaluation of the density of dislocations is made from the I-V characteristics, giving a value of 1.49 × 10^7 cm^-2.
基金supported by the National Natural Science Foundation of China(Grant Nos.62090014,62188102,62104184,62104178,and 62104179)the Fundamental Research Funds for the Central Universities of China(Grant Nos.XJS201102,XJS211101,XJS211106,and ZDRC2002)。
文摘An atomic-level controlled etching(ACE)technology is invstigated for the fabrication of recessed gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with high power added efficiency.We compare the recessed gate HEMTs with conventional etching(CE)based chlorine,Cl_(2)-only ACE and BCl^(3)/Cl_(2)ACE,respectively.The mixed radicals of BCl_(3)/Cl_(2)were used as the active reactants in the step of chemical modification.For ensuring precise and controllable etching depth and low etching damage,the kinetic energy of argon ions was accurately controlled.These argon ions were used precisely to remove the chemical modified surface atomic layer.Compared to the HEMTs with CE,the characteristics of devices fabricated by ACE are significantly improved,which benefits from significant reduction of etching damage.For BCl_(3)/Cl_(2)ACE recessed HEMTs,the load pull test at 17 GHz shows a high power added efficiency(PAE)of 59.8%with an output power density of 1.6 W/mm at Vd=10 V,and a peak PAE of 44.8%with an output power density of 3.2 W/mm at Vd=20 V in a continuous-wave mode.
文摘对 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℃ .
基金Project Supported bythe State Key Development Programfor Basic Research of China(2002CB311903)The Key Innovation Programof Chinese Academy of Sciences(KGCX2-SW-107)
