Optimal design of the multiple-apertures-GaN-based vertical HEMTs with $$\hbox {SiO}_{2}$$ SiO 2 current blocking layer

Abstract

Gallium nitride (GaN) based vertical high electron mobility transistor (HEMT) is very crucial for high power applications. Combination of advantageous material properties of GaN for high speed applications and novel vertical structure makes this device very beneficial for high power application. To improve the device performance especially in high drain bias condition, a novel GaN based vertical HEMT with silicon dioxide (SiO 2 ) current blocking layer (CBL) was reported recently. In this paper, effects of the thickness of CBL layer and the aperture length on the electrical and breakdown characteristics of GaN vertical HEMTs with SiO 2 CBL are simulated by using two-dimensional quantum-mechanically corrected device simulation. Intensive numerical study on the device enables us to optimize and conclude that devices with 0.5-µm-thick SiO 2 layer and 1-µm-long aperture will be beneficial considerations to improve the device performance. Notably, using the multiple apertures can effectively reduce the on-state conducting resistance of the device. On increasing the number of apertures, the drain current is increased but the breakdown voltage is decreased. Therefore, device with four apertures is taken as an optimized result. The maximum drain current of 84 mA B Yiming Li at V G = 1 V and V D = 30 V, and the breakdown voltage of 480 V have been achieved for the optimized device.

Analytical Model for Two-Dimensional Electron Gas Charge Density in Recessed-Gate GaN High-Electron-Mobility Transistors

“…GaN high-electron-mobility transistors (HEMTs) have shown great potential for use in high-power and high-frequency applications due to their wide bandgap and high electron mobility. 1,2 The defining feature of this device technology is the presence of a high-density two-dimensional electron gas (2DEG) at the AlGaN-GaN interface due to the strong spontaneous and piezoelectric polarization. However, this high 2DEG density leads to GaN HEMTs that are normally-ON (depletion-mode) switches, which is not suitable for power electronic applications because of safety and system cost concerns.…”

Gallium Nitride Normally-Off Vertical Field-Effect Transistor Featuring an Additional Back Current Blocking Layer Structure

“…Furthermore, note that the BV of the proposed device is improved significantly compared with the control one. Figure 12 summarizes the performance comparisons between the proposed BCBL-VFET and other reported GaN-based power devices including VFET, metal-oxide-semiconductor field-effect transistor (MOSFET), and HEMT devices [17][18][19][20][21][22][23][24][25]. It can be seen that the performance of the BCBL-VFET is closer to the GaN limit, compared with the control device and other work.…”