11.9 W Output Power at S-band from 1 mm AlGaN/GaN HEMTs

Abstract

We present radio-frequency (RF) power results of GaN-based high electron mobility transistors (HEMTs) with total gate widths (W g ) up to 1 mm. The AlGaN/GaN epi-structures are MOVPE-grown on 2-inches semi-insulating (s.i.) 4H-silicon carbide substrates. The HEMTs have been fabricated using an optimized process flow comprising a low-power Ar-based plasma after ohmic contact metallization, cleaning of the AlGaN surface prior to the Schottky gate metallization using a diluted ammonia (NH 4 OH) solution, and passivation of the AlGaN surface using a silicon nitride layer deposited by plasma enhanced chemical vapor deposition. We will show that the best RF power performance has been achieved by HEMTs with iron-doped GaN buffer layers (GaN:Fe). Devices with a total gate width of 1 mm yielded a maximum output power of 11.9 W at S-band (2 -4 GHz) under class AB bias conditions (V DS = 40 -60 V, and V GS = -4.65 --4.0 V).

Moving photoluminescence band in AlGaN/GaN heterostructures

“…It leads to the formation of a triangular shape potential in the GaN layer near the AlGaN/ GaN interface that accumulates high-density two-dimensional electron gas (2DEG) with the electron concentration and mobility exceeding 10 13 cm −2 and 1500 cm 2 V −1 s −1 at room temperature. This fact is used to fabricate high electron mobility transistors that are attractive candidates for the high voltage, high power operation at microwave frequencies [4][5][6][7][8][9][10].…”