Thin tungsten nitride （WNx） films were produced by reactive DC magnetron sputtering of tungsten in an Ar-N2 gas mixture. The films were used as Schottky contacts on AlGaN/GaN heterostructures. The Schottky behaviour...Thin tungsten nitride （WNx） films were produced by reactive DC magnetron sputtering of tungsten in an Ar-N2 gas mixture. The films were used as Schottky contacts on AlGaN/GaN heterostructures. The Schottky behaviours of WNx contact was investigated under various annealing conditions by current-voltage （I-V） measurements. The results show that the gate leakage current was reduced to 10-6 A/cm2 when the N2 flow is 400 mL/min. The results also show that the WNx contact improved the thermal stability of Schottky contacts, Finally, the current transport mechanism in WNx/AlGaN/GaN Schottky diodes has been investigated by means of I-V characterisation technique at various temperatures between 300 K and 523 K. ATE model with a Gaussian distribution of Schottky barrier heights （SBHs） is thought to be responsible for the electrical behaviour at temperatures lower than 523 K.展开更多
Ni/Au Schottky contacts with thicknesses of either 50（？）/50（？） or 600（？）/2000（？） were deposited on strained Al_（0.3）Ga_（0.7）N/GaN heterostructures.Using the measured C-V curves and I-V characteristics ...Ni/Au Schottky contacts with thicknesses of either 50（？）/50（？） or 600（？）/2000（？） were deposited on strained Al_（0.3）Ga_（0.7）N/GaN heterostructures.Using the measured C-V curves and I-V characteristics at room temperature,the calculated density of the two-dimensional electron-gas（2DEG） of the 600（？）/2000（？） thick Ni/Au Schottky contact is about 9.13×10^（12） cm^（-2） and that of the 50（？）/50（？） thick Ni/Au Schottky contact is only about 4.77×10^（12） cm^（-2）.The saturated current increases from 60.88 to 86.34 mA at a bias of 20 V as the thickness of the Ni/Au Schottky contact increases from 50（？）/50（？） to 600 A/2000 A.By self-consistently solving Schrodinger＇s and Poisson＇s equations,the polarization charge sheet density of the two samples was calculated,and the calculated results show that the polarization in the AlGaN barrier layer for the thick Ni/Au Schottky contact is stronger than the thin one.Thus,we attribute the results to the increased biaxial tensile stress in the Al_（0.3）Ga_（0.7）N barrier layer induced by the 600（？）/2000（？） thick Ni/Au Schottky contact.展开更多
文摘Thin tungsten nitride （WNx） films were produced by reactive DC magnetron sputtering of tungsten in an Ar-N2 gas mixture. The films were used as Schottky contacts on AlGaN/GaN heterostructures. The Schottky behaviours of WNx contact was investigated under various annealing conditions by current-voltage （I-V） measurements. The results show that the gate leakage current was reduced to 10-6 A/cm2 when the N2 flow is 400 mL/min. The results also show that the WNx contact improved the thermal stability of Schottky contacts, Finally, the current transport mechanism in WNx/AlGaN/GaN Schottky diodes has been investigated by means of I-V characterisation technique at various temperatures between 300 K and 523 K. ATE model with a Gaussian distribution of Schottky barrier heights （SBHs） is thought to be responsible for the electrical behaviour at temperatures lower than 523 K.
基金Project supported by the National Natural Science Foundation of China(No.10774090)the State Key Development Program for Basic Research of China(No.2007CB936602).
文摘Ni/Au Schottky contacts with thicknesses of either 50（？）/50（？） or 600（？）/2000（？） were deposited on strained Al_（0.3）Ga_（0.7）N/GaN heterostructures.Using the measured C-V curves and I-V characteristics at room temperature,the calculated density of the two-dimensional electron-gas（2DEG） of the 600（？）/2000（？） thick Ni/Au Schottky contact is about 9.13×10^（12） cm^（-2） and that of the 50（？）/50（？） thick Ni/Au Schottky contact is only about 4.77×10^（12） cm^（-2）.The saturated current increases from 60.88 to 86.34 mA at a bias of 20 V as the thickness of the Ni/Au Schottky contact increases from 50（？）/50（？） to 600 A/2000 A.By self-consistently solving Schrodinger＇s and Poisson＇s equations,the polarization charge sheet density of the two samples was calculated,and the calculated results show that the polarization in the AlGaN barrier layer for the thick Ni/Au Schottky contact is stronger than the thin one.Thus,we attribute the results to the increased biaxial tensile stress in the Al_（0.3）Ga_（0.7）N barrier layer induced by the 600（？）/2000（？） thick Ni/Au Schottky contact.
