Plasma etching damage to InGaAs/InP 2DEG material

Using the sample with a conventional source-drain structure of high electron mobility transistor (HEMT), the plasma etching damage to InGaAs/InP two dimensional electron gas (2DEG) material by reactive ion etching (RIE), magnetic enhanced RIE (MERIE) and inductively coupled plasma (ICP) etching was studied. In RIE/MERIE etching processes, either increase of RF power or decrease of operation pressure resulted in lineal decrease of saturated current. The damage induced by MERIE was obviously lower than RIE even under the same self-bias voltage, principally attributed to the lower mean ion energy in higher density plasma. In ICP etching process, the damage mainly resulted from the "applied bias voltage". The saturated current linearly decreased with increase of the bias voltage. Furthermore, the raising of inductively coupled power would cause dramatic dropping of saturated current under the presentation of bias voltage.