High frequency, high breakdown AlInAs/GaInAs junction modulated HEMT's (JHEMT's) with regrown ohmic contacts by MOCVD

Abstract

The authors present a technology for increasing the gate-drain breakdown of AlInAs/GaInAs HEMTs (high electron mobility transistors) to record values without substantial impact on other parameters such as I/sub dss/ and g/sub m/. The breakdown in these structures is dependent on the multiplication of electrons injected from the gate (gate leakage) and the source (source current) into the channel. In addition, holes are generated by high fields at the drain and are swept back into the gate and source electrodes. These phenomena can be suppressed by increasing the gate barrier height and alleviating the fields at the drain. In the present approach both have been achieved by incorporating a P+ -2DEG junction as the gate which modulates the 2DEG (two-dimensional electron gas) and by utilizing a selective regrowth of the source and drain regions by MOCVD (metal-organic chemical vapor deposition). The 1- mu m gate-length devices fabricated show a full channel current of 340 mA/mm, a transconductance of 240 mS/mm, and a gate-drain breakdown voltage of 30 V (L/sub GD/=1 mu m) at 1 mA/mm gate leakage.