A Novel Step–Doped Channel AlGaN/GaN HEMTs with Improved Breakdown Performance

Abstract

The AlGaN/GaN high electron mobility transistor with a step–doped channel (SDC–HEMT) is first proposed in this paper. The potential distribution and the electric field (E–field) distribution of the device are explored by the numerical approach and analytical approach simultaneously. By introducing extra dopants to the channel layer, the E–field distribution along the AlGaN/GaN heterojunction interface is reshaped, resulting in an improved breakdown characteristic. An optimized doping concentration gradient of channel layer of 2 × 1016 cm−3/step is proposed and verified by simulations. The breakdown voltage (BV) of the optimized SDC–HEMT reaches 1486 V with a 59.8% improvement compared with conventional AlGaN/GaN HEMT. In addition, the average E–field in the region between gate and drain improves from 1.5 to 2.5 MV/cm. Based on the equivalent potential method (EPM), an analytical model of the E–field and potential distribution is presented. The veracity and effectiveness of the proposed methodology is verified by the good agreement between the simulated and modeled results.

A Novel AlGaN/Si3N4 Compound Buffer Layer HEMT with Improved Breakdown Performances

“…At the same time, GaN-on-silicon is widely used owing to its low cost and large size, which can be integrated with Si-CMOS technology [ 10 , 11 ]. In recent years, there have been an increasing number of reports on high-performance AlGaN/GaN HEMT devices [ 12 , 13 , 14 , 15 , 16 , 17 ], however, there is still a large gap between the limits of GaN material properties and commercial devices. Researchers mainly use field plate technology or progressive transition layers to obtain a low specific on-resistance (R on,sp ) with a high breakdown voltage (BV), thereby realizing a higher figure-of-merits (FOM) (FOM = BV 2 /R on,sp ).…”

“…In the fabrication process, the field plate is connected to the gate and placed over the passivation layer. However, the improvement of the device performance depends on the lateral length of the field plate, and the breakdown voltage rises at the beginning and then declines with increasing field plate [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. At the same time, the field plate is equivalent to increasing the electrode overlapping area, which brings the corresponding parasitic capacitance and deteriorates the switching performance of the device.…”