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
lnA1N/GaN high-electron-mobility transistors （HEMTs） on SiC substrate were fabricated and character- ized. Several techniques, consisting of high electron density, 70 nm T-shaped gate, low ohmic contacts and a short...lnA1N/GaN high-electron-mobility transistors （HEMTs） on SiC substrate were fabricated and character- ized. Several techniques, consisting of high electron density, 70 nm T-shaped gate, low ohmic contacts and a short drain-source distance, are integrated to gain high device performance. The fabricated InA1N/GaN HEMTs exhibit a maximum drain saturation current density of 1.65 A/ram at Vgs = 1 V and a maximum peak transconductance of 382 mS/rnm. In addition, a unity current gain cut-off frequency （fT） of 162 GHz and a maximum oscillation frequency （fmax） of 176 GHz are achieved on the devices with the 70 nm gate length.展开更多
120 nm gate-length In_（0.7）Ga_（0.3）As/In_（0.52）Al_（0.48） As InP-based high electron mobility transitions（HEMTs） are fabricated by a new T-shaped gate electron beam lithograph（EBL） technology,which is achie...120 nm gate-length In_（0.7）Ga_（0.3）As/In_（0.52）Al_（0.48） As InP-based high electron mobility transitions（HEMTs） are fabricated by a new T-shaped gate electron beam lithograph（EBL） technology,which is achieved by the use of a PMMA/PMGI/ZEP520/PMGI four-layer photoresistor stack.These devices also demonstrate excellent DC and RF characteristics：the transconductance,maximum saturation drain-to-source current,threshold voltage,maximum current gain frequency,and maximum power-gain cutoff frequency of InGaAs/InAlAs HEMTs is 520 mS/mm,446 mA/mm, -1.0 V,141 GHz and 120 GHz,respectively.The material structure and all the device fabrication technology in this work were developed by our group.展开更多
200nm gate-length power InAlAs/InGaAs MHEMTs with T-shaped gate are characterized for DC, RF, and power performance. The MHEMTs show excellent DC output characteristics with an extrinsic transconductance of 510mS/ mm ...200nm gate-length power InAlAs/InGaAs MHEMTs with T-shaped gate are characterized for DC, RF, and power performance. The MHEMTs show excellent DC output characteristics with an extrinsic transconductance of 510mS/ mm and a threshold voltage of - 1.8V. The fT and fmax obtained for the 0.2μm × 100μm MHEMTs are 138 and 78GHz, respectively. Power characteristics are obtained under different frequencies. When input power （Pin） is - 0. 88dBm （or 2. 11dBm）,the MHEMTs exhibit high power characteristics at 8GHz. Output power （Pout） ,associated gain, power added efficiency （PAE） and density of Pout are 4. 05（13.79）dBm,14. 9（11.68）dB,67. 74（75.1）% ,254（239）mW/mm respectively. These promising results are on the path to the application of millimeter wave devices and integrated circuits with improved manufacturability over InP HEMT.展开更多
An ultralow specific on-resistance （Ron,sp） trench metal-oxide-semiconductor field effect transistor （MOSFET） with an improved off-state breakdown voltage （BV） is proposed. It features a U-shaped gate around the...An ultralow specific on-resistance （Ron,sp） trench metal-oxide-semiconductor field effect transistor （MOSFET） with an improved off-state breakdown voltage （BV） is proposed. It features a U-shaped gate around the drift region and an oxide trench inserted in the drift region （UG MOSFET）. In the on-state, the U-shaped gate induces a high density electron accumulation layer along its sidewall, which provides a low-resistance current path from the source to the drain, realizing an ultralow Ron,sp. The value of Ron,sp is almost independent of the drift doping concentration, and thus the UG MOSFET breaks through the contradiction relationship between R p and the off-state BV. Moreover, the oxide trench folds the drift region, enabling the UG MOSFET to support a high BV with a shortened cell pitch. The UG MOSFET achieves an Ron,sp of 2 mΩ·cm^2 and an improved BV of 216 V, superior to the best existing state-of-the-art transistors at the same BV level展开更多
The ever-decreasing size of transistors requires effectively electrostatic control over ultra-thin semiconductor body.Rational design of the gate configuration can fully persevere the intrinsic property of two-dimensi...The ever-decreasing size of transistors requires effectively electrostatic control over ultra-thin semiconductor body.Rational design of the gate configuration can fully persevere the intrinsic property of two-dimensional(2 D)semiconductors.Here we design and demonstrate a 2 D Mo S_(2) transistor with omega-shaped gate,in which the local gate coupling is enhanced by the non-planar geometry.The omega-shaped non-planar transistors exhibit a high current of 0.89 A/lm and transconductance of32.7 l S/lm.The high performance and desirable current saturation promise the construction of robust logic gate.The inverters show a voltage gain of 26.6 and an ideal total margin nearly 89%.We also assemble NOT-AND(NAND)gate on an individual Mo S_(2) flake,and the constructed NAND gate demonstrates the universal functionality of the transistors as well.This work provides an alternative strategy to fully take the advantages of 2 D materials for high-performance field-effect transistors.展开更多
A novel vertical InN/InGaN heterojunction tunnel FET with hetero T-shaped gate as well as polarization-doped source and drain region(InN-Hetero-TG-TFET)is proposed and investigated by Silvaco-Atlas simulations for the...A novel vertical InN/InGaN heterojunction tunnel FET with hetero T-shaped gate as well as polarization-doped source and drain region(InN-Hetero-TG-TFET)is proposed and investigated by Silvaco-Atlas simulations for the first time.Compared with the conventional physical doping TFET devices,the proposed device can realize the P-type source and N-type drain region by means of the polarization effect near the top InN/InGaN and bottom InGaN/InN heterojunctions respectively,which could provide an effective solution of random dopant fluctuation(RDF)and the related problems about the high thermal budget and expensive annealing techniques due to ion-implantation physical doping.Besides,due to the hetero T-shaped gate,the improvement of the on-state performance can be achieved in the proposed device.The simulations of the device proposed here in this work show ION of 4.45×10^(-5)A/μm,ION/IOFF ratio of 10^(13),and SS_(avg)of 7.5 mV/dec in InN-Hetero-TG-TFET,which are better than the counterparts of the device with a homo T-shaped gate(InN-Homo-TG-TFET)and our reported lateral polarization-induced InN-based TFET(PI-InN-TFET).These results can provide useful reference for further developing the TFETs without physical doping process in low power electronics applications.展开更多
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.
基金supported by the National Natural Science Foundation of China(No.61306113)
文摘lnA1N/GaN high-electron-mobility transistors （HEMTs） on SiC substrate were fabricated and character- ized. Several techniques, consisting of high electron density, 70 nm T-shaped gate, low ohmic contacts and a short drain-source distance, are integrated to gain high device performance. The fabricated InA1N/GaN HEMTs exhibit a maximum drain saturation current density of 1.65 A/ram at Vgs = 1 V and a maximum peak transconductance of 382 mS/rnm. In addition, a unity current gain cut-off frequency （fT） of 162 GHz and a maximum oscillation frequency （fmax） of 176 GHz are achieved on the devices with the 70 nm gate length.
基金Project supported by the National Natural Science Foundation of China(No.60806024)the Fundamental Research Funds for the Central Universities,China(No.XDJK2009C020).
文摘120 nm gate-length In_（0.7）Ga_（0.3）As/In_（0.52）Al_（0.48） As InP-based high electron mobility transitions（HEMTs） are fabricated by a new T-shaped gate electron beam lithograph（EBL） technology,which is achieved by the use of a PMMA/PMGI/ZEP520/PMGI four-layer photoresistor stack.These devices also demonstrate excellent DC and RF characteristics：the transconductance,maximum saturation drain-to-source current,threshold voltage,maximum current gain frequency,and maximum power-gain cutoff frequency of InGaAs/InAlAs HEMTs is 520 mS/mm,446 mA/mm, -1.0 V,141 GHz and 120 GHz,respectively.The material structure and all the device fabrication technology in this work were developed by our group.
基金supported by the State Key Development Programfor Basic Research of China(No.G2002CB311901)the Equipment Investigation Programin Advance(No.61501050401C)the Dean Fund of the Institute of Microelectronics,Chinese Academy of Sciences,(No.O6SB124004)~~
文摘200nm gate-length power InAlAs/InGaAs MHEMTs with T-shaped gate are characterized for DC, RF, and power performance. The MHEMTs show excellent DC output characteristics with an extrinsic transconductance of 510mS/ mm and a threshold voltage of - 1.8V. The fT and fmax obtained for the 0.2μm × 100μm MHEMTs are 138 and 78GHz, respectively. Power characteristics are obtained under different frequencies. When input power （Pin） is - 0. 88dBm （or 2. 11dBm）,the MHEMTs exhibit high power characteristics at 8GHz. Output power （Pout） ,associated gain, power added efficiency （PAE） and density of Pout are 4. 05（13.79）dBm,14. 9（11.68）dB,67. 74（75.1）% ,254（239）mW/mm respectively. These promising results are on the path to the application of millimeter wave devices and integrated circuits with improved manufacturability over InP HEMT.
基金Supported by the National Natural Science Foundation of China under Grant No 61376079the Fundamental Research Funds for the Central Universities under Grant No ZYGX2013J043
文摘An ultralow specific on-resistance （Ron,sp） trench metal-oxide-semiconductor field effect transistor （MOSFET） with an improved off-state breakdown voltage （BV） is proposed. It features a U-shaped gate around the drift region and an oxide trench inserted in the drift region （UG MOSFET）. In the on-state, the U-shaped gate induces a high density electron accumulation layer along its sidewall, which provides a low-resistance current path from the source to the drain, realizing an ultralow Ron,sp. The value of Ron,sp is almost independent of the drift doping concentration, and thus the UG MOSFET breaks through the contradiction relationship between R p and the off-state BV. Moreover, the oxide trench folds the drift region, enabling the UG MOSFET to support a high BV with a shortened cell pitch. The UG MOSFET achieves an Ron,sp of 2 mΩ·cm^2 and an improved BV of 216 V, superior to the best existing state-of-the-art transistors at the same BV level
基金supported by the National Key Research and Development Program of China(2018YFA0703704 and2018YFB0406603)China National Funds for Distinguished Young Scientists(61925403)+2 种基金the National Natural Science Foundation of China(61851403,51872084,61704052,61811540408,and61704051)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000)in partly by the Key Research and Development Plan of Hunan Province(2018GK2064)。
文摘The ever-decreasing size of transistors requires effectively electrostatic control over ultra-thin semiconductor body.Rational design of the gate configuration can fully persevere the intrinsic property of two-dimensional(2 D)semiconductors.Here we design and demonstrate a 2 D Mo S_(2) transistor with omega-shaped gate,in which the local gate coupling is enhanced by the non-planar geometry.The omega-shaped non-planar transistors exhibit a high current of 0.89 A/lm and transconductance of32.7 l S/lm.The high performance and desirable current saturation promise the construction of robust logic gate.The inverters show a voltage gain of 26.6 and an ideal total margin nearly 89%.We also assemble NOT-AND(NAND)gate on an individual Mo S_(2) flake,and the constructed NAND gate demonstrates the universal functionality of the transistors as well.This work provides an alternative strategy to fully take the advantages of 2 D materials for high-performance field-effect transistors.
基金the Key Research and Development Program of Shaanxi Province,China(Grant No.2020ZDLGY03-05)the National Natural Science Foundation of China(Grant No.61574112).
文摘A novel vertical InN/InGaN heterojunction tunnel FET with hetero T-shaped gate as well as polarization-doped source and drain region(InN-Hetero-TG-TFET)is proposed and investigated by Silvaco-Atlas simulations for the first time.Compared with the conventional physical doping TFET devices,the proposed device can realize the P-type source and N-type drain region by means of the polarization effect near the top InN/InGaN and bottom InGaN/InN heterojunctions respectively,which could provide an effective solution of random dopant fluctuation(RDF)and the related problems about the high thermal budget and expensive annealing techniques due to ion-implantation physical doping.Besides,due to the hetero T-shaped gate,the improvement of the on-state performance can be achieved in the proposed device.The simulations of the device proposed here in this work show ION of 4.45×10^(-5)A/μm,ION/IOFF ratio of 10^(13),and SS_(avg)of 7.5 mV/dec in InN-Hetero-TG-TFET,which are better than the counterparts of the device with a homo T-shaped gate(InN-Homo-TG-TFET)and our reported lateral polarization-induced InN-based TFET(PI-InN-TFET).These results can provide useful reference for further developing the TFETs without physical doping process in low power electronics applications.
