Abstract
A 2-D simulation of off-state breakdown voltage (VBD) for AlGaN/GaN high electron mobility transistors (HEMTs) with multi field-plates (FPs) is presented in this paper. The effect of geometrical variables of FP and insulator layer on electric field distribution and VBD are investigated systematically. The FPs can modulate the potential lines and distribution of an electric field, and the insulator layer would influence the modulation effect of FPs. In addition, we designed a structure of HEMT which simultaneously contains gate FP, source FP and drain FP. It is found that the VBD of AlGaN/GaN HEMTs can be improved greatly with the corporation of gate FP, source FP and drain FP. We achieved the highest VBD in the HEMT contained with three FPs by optimizing the structural parameters including length of FPs, thickness of FPs, and insulator layer. For HEMT with three FPs, FP-S alleviates the concentration of the electric field more effectively. When the length of the source FP is 24 μm and the insulator thickness between the FP-S and the AlGaN surface is 1950 nm, corresponding to the average electric field of about 3 MV/cm at the channel, VBD reaches 2200 V. More importantly, the 2D simulation model is based on a real HMET device and will provide guidance for the design of a practical device.
Highlights
Gallium nitride (GaN)-based high electron mobility transistor (HEMT) has become an attractive candidate for high power applications, due to integrating lots of outstanding physical properties like high breakdown voltage, high frequency application and low on-resistance [1,2,3]
From the perspective of field-plate position, FPs can be divided into gate field-plate (FP-G), source field plate (FP-S), and drain field plate (FP-D)
The FP-S is usually used in the GaN-based HEMTs in combination with the gate field-plate, is usuallya used the GaN-based in combination with the gate field-plate, with theThe aimFP-S
Summary
Gallium nitride (GaN)-based high electron mobility transistor (HEMT) has become an attractive candidate for high power applications, due to integrating lots of outstanding physical properties like high breakdown voltage, high frequency application and low on-resistance [1,2,3]. Toshiki Kabemura et al made a 2-D analysis of breakdown characteristics of FP HEMTs with a high-k passivation layer, confirming that the VBD would increase with relative permittivity increasing [19]. The incorporation of FP-S and FP-D was considered to be an effective way to improve VBD and reduce the on-resistance to about. It is necessary to combine the three FPs. Up to now, the properties of HEMT with FP-G, FP-S and FP-D simultaneously are seldom discussed. The effect of geometrical variables of FP and insulator layer on field distribution and VBD were investigated systematically. The FP-G, FP-S and FP-D are employed simultaneously in an AlGaN/GaN HEMT to improve VBD effectively. The parameters including length of FPs, thickness of FPs, and insulator layer of FPs were optimized for improving VBD. The breakdown characteristics of HEMT with FP-G, FP-S and FP-D were simultaneously discussed
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