A model of novel triangular electrode metal-semiconductor-metal(TEMSM)and conventional electrode metal-semiconductor-metal(CEMSM)detectors is established by utilizing the ISE-TCAD simulator.By comparing the simulated ...A model of novel triangular electrode metal-semiconductor-metal(TEMSM)and conventional electrode metal-semiconductor-metal(CEMSM)detectors is established by utilizing the ISE-TCAD simulator.By comparing the simulated results of TEMSM and CEMSM with experimental data,the model validity is verified and the TEMSM detector shows a superiority of a 113%photocurrent increase of 25.4 nA and similar low dark current of 3.16 pA at 30 V bias over the CEMSM device.Furthermore,the electrode angleα,width W and spacing S are optimized to obtain the enhanced device features including high UV−to-visible rejection ratio and large responsivity,etc.Under 30 V bias,the maximum UV-to-visible rejection ratio,comparable responsivity and external quantum efficiency at 310 nm are 13049,0.1712 A/W and 68.48%for a TEMSM detector with device parameters ofα=60°,W=3μm and S=4μm,respectively.展开更多
An improved structure of silicon carbide metal-semiconductor field-effect transistors （MESFET） is proposed for high power microwave applications. Numerical models for the physical and electrical mechanisms of the de...An improved structure of silicon carbide metal-semiconductor field-effect transistors （MESFET） is proposed for high power microwave applications. Numerical models for the physical and electrical mechanisms of the device are presented, and the static and dynamic electrical performances are analysed. By comparison with the conventional structure, the proposed structure exhibits a superior frequency response while possessing better DC characteristics. A p-type spacer layer, inserted between the oxide and the channel, is shown to suppress the surface trap effect and improve the distribution of the electric field at the gate edge. Meanwhile, a lightly doped n-type buffer layer under the gate reduces depletion in the channel, resulting in an increase in the output current and a reduction in the gate-capacitance. The structural parameter dependences of the device performance are discussed, and an optimized design is obtained. The results show that the maximum saturation current density of 325 mA/mm is yielded, compared with 182 mA/mm for conventional MESFETs under the condition that the breakdown voltage of the proposed MESFET is larger than that of the conventional MESFET, leading to an increase of 79% in the output power density. In addition, improvements of 27% cut-off frequency and 28% maximum oscillation frequency are achieved compared with a conventional MESFET, respectively.展开更多
A new 4H silicon carbide metal semiconductor field-effect transistor （4H-SiC MESFET） structure with a buffer layer between the gate and the channel layer is proposed in this paper for high power microwave applicatio...A new 4H silicon carbide metal semiconductor field-effect transistor （4H-SiC MESFET） structure with a buffer layer between the gate and the channel layer is proposed in this paper for high power microwave applications. The physics-based analytical models for calculating the performance of the proposed device are obtained by solving one- and two-dimensional Poisson＇s equations. In the models, we take into account not only two regions under the gate but also a third high field region between the gate and the drain which is usually omitted. The direct-current and the alternating- current performances for the proposed 4H-SiC MESFET with a buffer layer of 0.2 ~tm are calculated. The calculated results are in good agreement with the experimental data. The current is larger than that of the conventional structure. The cutoff frequency （fT） and the maximum oscillation frequency （fmax） are 20.4 GHz and 101.6 GHz, respectively, which are higher than 7.8 GHz and 45.3 GHz of the conventional structure. Therefore, the proposed 4H-SiC MESFET structure has better power and microwave performances than the conventional structure.展开更多
基金by Supported by the National Defense Pre-Research Foundation of China under Grant Nos 51323040118,513080302.
文摘A model of novel triangular electrode metal-semiconductor-metal(TEMSM)and conventional electrode metal-semiconductor-metal(CEMSM)detectors is established by utilizing the ISE-TCAD simulator.By comparing the simulated results of TEMSM and CEMSM with experimental data,the model validity is verified and the TEMSM detector shows a superiority of a 113%photocurrent increase of 25.4 nA and similar low dark current of 3.16 pA at 30 V bias over the CEMSM device.Furthermore,the electrode angleα,width W and spacing S are optimized to obtain the enhanced device features including high UV−to-visible rejection ratio and large responsivity,etc.Under 30 V bias,the maximum UV-to-visible rejection ratio,comparable responsivity and external quantum efficiency at 310 nm are 13049,0.1712 A/W and 68.48%for a TEMSM detector with device parameters ofα=60°,W=3μm and S=4μm,respectively.
基金Project supported by the National Science Fund for Distinguished Young Scholars of China(Grant No.60725415)the National Natural Science Foundation of China(Grant No.60606006)the Pre-research Foundation of China(Grant No.51308030201)
文摘An improved structure of silicon carbide metal-semiconductor field-effect transistors （MESFET） is proposed for high power microwave applications. Numerical models for the physical and electrical mechanisms of the device are presented, and the static and dynamic electrical performances are analysed. By comparison with the conventional structure, the proposed structure exhibits a superior frequency response while possessing better DC characteristics. A p-type spacer layer, inserted between the oxide and the channel, is shown to suppress the surface trap effect and improve the distribution of the electric field at the gate edge. Meanwhile, a lightly doped n-type buffer layer under the gate reduces depletion in the channel, resulting in an increase in the output current and a reduction in the gate-capacitance. The structural parameter dependences of the device performance are discussed, and an optimized design is obtained. The results show that the maximum saturation current density of 325 mA/mm is yielded, compared with 182 mA/mm for conventional MESFETs under the condition that the breakdown voltage of the proposed MESFET is larger than that of the conventional MESFET, leading to an increase of 79% in the output power density. In addition, improvements of 27% cut-off frequency and 28% maximum oscillation frequency are achieved compared with a conventional MESFET, respectively.
基金Project supported by the Pre-research Foundation from the National Ministries and Commissions of China(Grant No.51308030201)
文摘A new 4H silicon carbide metal semiconductor field-effect transistor （4H-SiC MESFET） structure with a buffer layer between the gate and the channel layer is proposed in this paper for high power microwave applications. The physics-based analytical models for calculating the performance of the proposed device are obtained by solving one- and two-dimensional Poisson＇s equations. In the models, we take into account not only two regions under the gate but also a third high field region between the gate and the drain which is usually omitted. The direct-current and the alternating- current performances for the proposed 4H-SiC MESFET with a buffer layer of 0.2 ~tm are calculated. The calculated results are in good agreement with the experimental data. The current is larger than that of the conventional structure. The cutoff frequency （fT） and the maximum oscillation frequency （fmax） are 20.4 GHz and 101.6 GHz, respectively, which are higher than 7.8 GHz and 45.3 GHz of the conventional structure. Therefore, the proposed 4H-SiC MESFET structure has better power and microwave performances than the conventional structure.
