Improving Performance and Breakdown Voltage in Normally-Off GaN Recessed Gate MIS-HEMTs Using Atomic Layer Etching and Gate Field Plate for High-Power Device Applications

Abstract

A typical method for normally-off operation, the metal–insulator–semiconductor-high electron mobility transistor (MIS-HEMT) has been investigated. Among various approaches, gate recessed MIS-HEMT have demonstrated a high gate voltage sweep and low leakage current characteristics. Despite their high performance, obtaining low-damage techniques in gate recess processing has so far proven too challenging. In this letter, we demonstrate a high current density and high breakdown down voltage of a MIS-HEMT with a recessed gate by the low damage gate recessed etching of atomic layer etching (ALE) technology. After the remaining 3.7 nm of the AlGaN recessed gate was formed, the surface roughness (Ra of 0.40 nm) was almost the same as the surface without ALE (no etching) as measured by atomic force microscopy (AFM). Furthermore, the devices demonstrate state-of-the-art characteristics with a competitive maximum drain current of 608 mA/mm at a VG of 6 V and a threshold voltage of +2.0 V. The devices also show an on/off current ratio of 109 and an off-state hard breakdown voltage of 1190 V. The low damage of ALE technology was introduced into the MIS-HEMT with the recessed gate, which effectively reduced trapping states at the interface to obtain the low on-resistance (Ron) of 6.8 Ω·mm and high breakdown voltage performance.

Study of 1500 V AlGaN/GaN High-Electron-Mobility Transistors Grown on Engineered Substrates

“…The low-temperature (5 K) photoluminescence (PL) spectrum served as a diagnostic tool to assess the material quality, carrier concentration, and trap states in GaN HEMT devices. In contrast, we carried out previous work on an optimal GaN on Si device as a reference [16]. Regarding material quality, the sharpness and the positioning of the near-band-edge emission peak were crucial indicators.…”

Improvement Performance of p-GaN Gate High-Electron-Mobility Transistors with GaN/AlN/AlGaN Barrier Structure

“…The study of p-GaN gate breakdown behavior under forward bias conditions has attracted widespread attention in this field. Special attention was dedicated to understanding this breakdown phenomenon in [22], where breakdown events were observed to be associated with the formation of percolation paths within the depletion region of the p-GaN layer, especially in the region close to the metal interface. Similarly, [23] provided insights into the breakdown mechanism by emphasizing avalanche multiplication within the space charge region of the Schottky metal/p-GaN junction.…”