Vertical GaN p+-n junction diode with ideal avalanche capability grown by halide vapor phase epitaxy

Abstract

A vertical GaN p+-n junction diode with an ideal breakdown voltage was grown by halide vapor phase epitaxy (HVPE). A steep p+-n interface was observed even with the use of the HVPE method. No Si-accumulating layer was formed at the p+-n interface because of the continuous HVPE growth from the n-type drift layer to the p-type layer. This method provides improved electrical properties compared with the regrowth of p-type GaN layers. The minimum ideality factor of approximately 1.6 was obtained. The breakdown voltage increased from 874 to 974 V with the increase in the temperature from 25 to 200 °C, which suggests that avalanche multiplication causes the breakdown. The temperature-dependent breakdown voltage was in good agreement with the breakdown voltage calculated using the ideal critical electric field. These results indicate that HVPE is promising for the fabrication of vertical GaN power devices.

Vertical GaN-on-GaN Trench Junction Barrier Schottky Diodes With a Slanted Sidewall

“…The breakdown voltage almost linearly increased with the increasing temperature, which shows a positive coefficient between V BR and temperature. With the increasing temperature, the electrons need higher temperature to gain the threshold energy to cause impact ionization, due to the increased phonon scattering, which suggests the breakdown mechanism of the fabricated devices is avalanche breakdown [6], [31]. At 298 K, the fabricated devices have a low reverse current density of 10 −7 A/cm 2 [32].…”

“…gallium nitride (GaN) is recognized as an important semiconductor material, because of its excellent properties such as the wide bandgap (3.4 eV), low dielectric constant (∼9) and high breakdown field (∼3.4 MV/cm), and good thermal conductivity (∼1.3 W/cm-K) [1], [2], [3], [4]. The most widely studied GaN-based power diodes are mainly divided into lateral and vertical structures [5], [6]. The lateral diodes have some shortcomings such as large chip area, and low forward current density which limit applications of GaN-based lateral devices.…”

Ga-polar GaN Camel diode enabled by a low-cost Mg-diffusion process

“…The ideality factor of GaN Camel diodes was observed to be marginally higher than the regular GaN SBD. Nevertheless, a significantly lower f B together with a lower ideality factor observed in the GaN Camel diodes compared to the traditional GaN PN junction diodes 35,36) indicate that the Camel diodes investigated in this work are likely to be unipolar. The thickness of the p-GaN layer (t pGaN ) and its doping (N A ) are important parameters of Camel diode device-design.…”

Correlating Interface and Border Traps With Distinctive Features of C–V Curves in Vertical Al2O3/GaN MOS Capacitors

“…As a result, relatively small-area devices can be designed, which can operate in the kV range and are naturally immune from surface-and buffer-related, currentcollapse and dynamic R ON effects, that instead affect lateral device operation [3], [4], [5], [6], [7]. In addition, avalanche capability has been demonstrated in vertical GaN devices [8], [9], [10], [11] allowing for reliable, unclamped inductive switching in converter circuits [10].…”