Recovery Performance of Ge-Doped Vertical GaN Schottky Barrier Diodes

Yong Chen,Hong Gu,Xinke Liu,Jiale Wang,Xuanhua Deng,Chunyu Zhang,Ke Xu,Feifei Tian

doi:10.1186/s11671-019-2872-7

Abstract

Vertical GaN Schottky barrier diodes (SBDs) were fabricated on Ge-doped free-standing GaN substrates. The crystal quality of the SBDs was characterized by cathode luminescence measurement, and the dislocation density was determined to be ~ 1.3 × 106 cm− 2. With the electrical performance measurements conducted, the SBDs show a low turn-on voltage Von (0.70~0.78 V) and high current Ion/Ioff ratio (9.9 × 107~1.3 × 1010). The reverse recovery characteristics were investigated. The reverse recovery time was obtained to be 15.8, 16.2, 18.1, 21.22, and 24.5 ns for the 100-, 200-, 300-, 400-, and 500-μm-diameter SBDs, respectively. Meanwhile, the reverse recovery time and reverse recovery charge both show a significant positive correlation with the electrode area.

Highlights

A wide band gap semiconductor—such as Gallium nitride (GaN)—with the inherent advantages, has attracted tremendous research attention for the next-generation electronics devices, in the field of high frequency, high power, and high performance [1,2,3,4,5,6]
The schematic of device structures for the fabricated Schottky barrier diodes (SBDs) is displayed in Fig. 1a, which mainly consists of a 390-μm FS n+-GaN substrate and a 9-μm n−-GaN drift layer
The turn-on voltage Von of vertical SBDs is determined to be 0.70, 0.76, 0.72, 0.70, and 0.78 V, respectively, with the electrode diameters increasing from 100 to 500 μm. These results indicate a good electronic property was obtained for the vertical SBDs

Summary

Introduction

A wide band gap semiconductor—such as GaN—with the inherent advantages, has attracted tremendous research attention for the next-generation electronics devices, in the field of high frequency, high power, and high performance [1,2,3,4,5,6]. Thanks to the developments of hydride vapor phase epitaxy (HVPE), low dislocation density (≤ 106 cm− 2) GaN substrates are commercially available [7,8,9,10]. GaN-based Schottky barrier diode (SBD) is a vital component in the switching devices. Differed from a bipolar diode, the SBD with its unipolar nature greatly reduces the minority carrier storage effect and correspondingly offers a high switching speed with low reverse recovery loss. Few groups have conducted a systematic study of the reverse recovery characteristics for vertical GaN SBDs [13,14,15,16,17], of which studies focused more on the comparison of the switching time in different

Methods

Results

Conclusion