Oxygen Ion Implantation Isolation Planar Process for AlGaN/GaN HEMTs

Abstract

Abstract-A multienergy oxygen ion implantation process was demonstrated to be compatible with the processing of highpower microwave AlGaN/GaN high electron mobility transistors (HEMTs). HEMTs that are isolated by this process exhibited gate-lag-and drain-lag-free operation. A maximum output power density of 5.3 W/mm at V gs = −4 V and V ds = 50 V and a maximum power added efficiency of 51.5% at V gs = −4 V and V ds = 30 V at 3 GHz were demonstrated on HEMTs without field plates on sapphire substrate. This isolation process results in planar HEMTs, circumventing potential problems with enhanced gate leakage due to the gate contacting the 2-D electron gas at the mesa sidewall.Index Terms-GaN, high electron mobility transistors (HEMTs), implantation, power density, pulsed I-V , transient.

Leakage current by Frenkel–Poole emission in Ni/Au Schottky contacts on Al0.83In0.17N/AlN/GaN heterostructures

“…2 Several investigations have been conducted for the basic mechanisms of gate leakage current, 4-10 and leakage current reduction. 11 Zhang et al 7 analyzed the leakage current mechanisms in the Schottky contacts of both n-GaN and AlGaN/GaN at different temperatures and concluded that tunneling current dominates at temperatures below 150 K, whereas the Frenkel-Poole emission dominates at temperatures higher than 250 K. Miller et al 8 have shown that the reverse-bias leakage in AlGaN/GaN can be analyzed in a conventional tunneling model. The effects of the dislocations and defects states, in the reverse-bias leakage, have been suggested by several studies for GaN and Al x Ga 1−x N heterostructures 4,6,7 wherein defects, in particular dislocations, might play an important role in reverse-bias leakage.…”

The Effect of Forward Gate Bias Stress on the Noise Performance of Mesa Isolated GaN HEMTs

“…Doing the analysis in Section IV using the results from [7], where the devices withstood a gate current of 900 mA/mm and voltage of 3.5 V without severe degradation, would result in an optimal bias resistance of 30 Ω • mm, giving a maximum input power of 43 dBm for a 2 × 50 μm device. Minimization of mesa leakage or use of other methods such as ion implantation, which can provide device isolation without the formation of a mesa where the GaN channel is in contact with the gate metal [14], could thus be essential for robust LNA design.…”

A new AlON buffer layer for RF-MBE growth of AlN on a sapphire substrate

“…Using this method, we obtained high-quality nitride layers grown by metalorganic vapor phase epitaxy (MOVPE). The undoped GaN shows resistance higher than 100 k ohm/sheet and AlGaN/GaN heterostructure shows high electron mobility of 1760 cm 2 /V, meaning that these characteristics are favorable especially for an AlGaN/ GaN heterostructure field effect transistor [6]. In addition to the growth of such a high quality nitride layer, the growth process using this AlON buffer layer reduces the growth time and the number of the growth parameters compared with the two step growth using a LT buffer layer.…”