Optimization design on breakdown voltage of AlGaN/GaN high-electron mobility transistor

Abstract

Simulations are carried out to explore the possibility of achieving high breakdown voltage of GaN HEMT (high-electron mobility transistor). GaN cap layers with gradual increase in the doping concentration from 2 × 1016 to 5 × 1019 cm−3 of N-type and P-type cap are investigated, respectively. Simulation results show that HEMT with P-doped GaN cap layer shows more potential to achieve higher breakdown voltage than N-doped GaN cap layer under the same doping concentration. This is because the ionized net negative space charges in P-GaN cap layer could modulate the surface electric field which makes more contribution to RESURF effect. Furthermore, a novel GaN/AlGaN/GaN HEMT with P-doped GaN buried layer in GaN buffer between gate and drain electrode is proposed. It shows enhanced performance. The breakdown voltage of the proposed structure is 640 V which is increased by 12% in comparison to UID (un-intentionally doped) GaN/AlGaN/GaN HEMT. We calculated and analyzed the distribution of electrons' density. It is found that the depleted region is wider and electric field maximum value is induced at the left edge of buried layer. So the novel structure with P-doped GaN buried layer embedded in GaN buffer has the better improving characteristics of the power devices.

Breakdown Voltage Enhancement in AlGaN HEMTs with Local p-Doped Region in the Back-Barrier

“…When the doping concentration was 7 × 10 16 cm −3 , the peak electric field decreased by 3.06 × 10 5 V/cm, and the BV increased to 1179.21 V correspondingly, with an increase of about 11%. That means that the p-type doped region can weaken the electric field because there is a space charge region in the back-barrier layer due to the reversed PN junction, which is formed by a hole in the p-doped region and the electron in the backbarrier layer [15,19]. The positive electron in a doped region can attract part of the electric field, resulting in a rise in another peak in the electric field distribution.…”

Simulation of AlGaN/GaN HEMTs’ Breakdown Voltage Enhancement Using Gate Field-Plate, Source Field-Plate and Drain Field Plate

“…For investigating the impact of FP-G and FP-S on the capacitances, Aamir et al modeled the bias dependence of terminal capacitances, and the proposed model is in excellent agreement with measured data [20]. Meanwhile, the incorporation of FP-S and FP-D was considered to be an effective way to improve V BD and reduce the on-resistance to about 0.6 mΩ•cm 2 [21]. However, in comparison with FP-G and FP-S, FP-D is rarely induced to enhance V BD but mostly induced to improve reverse breakdown voltage [22].…”

“…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]. For power devices, the property of high breakdown voltage is particularly significant.…”

Investigation of ON-State Breakdown Mechanism in AlGaN/GaN HEMTs with AlGaN Back Barrier

“…GaN-based high-electron-mobility transistors (HEMTs) are especially attractive for next-generation RF/microwave power amplifiers and power switching applications, as a result of their high breakdown electric field and polarization-induced high-mobility, as well as high-density 2D electron gas (2DEG) at the AlGaN/GaN hetero-interface [1][2][3][4]. Intensive efforts have been dedicated to the mechanism of the three-terminal OFF-state breakdown BV OFF characteristics that determine the power range of GaN-based power devices [5][6][7][8].…”