Leakage current reduction in β-Ga2O3 Schottky barrier diode with p-NiOx guard ring

Abstract

A β-Ga2O3 Schottky barrier diode (SBD) with a p-type NiOx guard ring was fabricated, and the reverse leakage and subthreshold leakage current reduction was found at high temperatures from temperature-dependent I–V characteristics. The functional mechanisms of NiOx as edge termination on leakage reduction were studied. NiOx can increase the barrier height and passivate the defects at the interface, resulting in the suppression of subthreshold leakage and elimination of current crowding effect confirmed by a thermal emission microscope. From the temperature-dependent x-ray photoelectron spectroscopy characteristics, more holes generated to deplete Ga2O3 at higher temperatures were found. It leads to reduce the reverse leakage current. The small-polaron transportation in NiOx is proposed to argue the implausibility of the leakage conduction in NiOx. This work will offer critical physical insight and a valuable route for developing low-leakage Ga2O3 SBDs.

(Invited) NiO/ β-(Al x Ga1-x )2O3 /Ga2O3 Heterojunction Lateral Rectifiers with Reverse Breakdown Voltage > 7kV

“…This is the highest reported for lateral rectifiers and shows the value of both the NiO gate structure and the inclusion of the wider band gap of the β-(Al x Ga 1-x ) 2 O 3 alloy. It is not expected there is significant leakage conduction contribution from the NiO layer due to formation of polarons in this material (45)(46)(47)(48) , making this a good choice as the p-side of the heterojunction. However, although the breakdown voltage is quite high, the Ron is extremely high as well in this lateral structure.…”

A Review of β-Ga2O3 Power Diodes

“…These developments convincingly demonstrate the potential for p-NiO termination extension structures in β-Ga2O3 power devices. [245]; (e) β-Ga2O3 SBD with edge termination extension and field plate structure [246]; (f) β-Ga2O3 SJ-SBDs [247].…”

“…Device robustness was confirmed under dynamic voltage conditions, withstanding breakdown at 2.2 kV in unclamped inductive switching (UIS) tests. Furthermore, the SJ-SBDs demonstrated no Integrating p-NiO within the edge termination structure also enables the formation of an edge termination extension structure, as depicted in Figure 14d [245]. Compared to a simple structure, the BV of the device was increased from 356 V to 1539 V, and p-NiO x effectively passivated the damage caused by dry-etching, yielding ideality factors close to 1 across varying temperatures, albeit with a notable reduction in forward current.…”

“…Figure 14. Device schematic of (a) β-Ga2O3 SBDs with p-NiO JTE [242]; (b) β-Ga2O3 SBDs with NiO stair-shaped JTE [243]; (c) NiO/β-Ga2O3 HJDs with NiO stair-shaped JTE [244]; (d) β-Ga2O3 SBDs with p-NiOx edge termination extension structure[245]; (e) β-Ga2O3 SBD with edge termination extension and field plate structure[246]; (f) β-Ga2O3 SJ-SBDs[247].…”