A selective gate recess process utilizing MBE-grown In/sub 0.5/Ga/sub 0.5/P etch-stop layers for GaAs-based FET technologies

A selective recess process for GaAs-based FETs that utilizes etch-stop layers comprised of In/sub 0.5/Ga/sub 0.5/P is demonstrated. The material was grown by molecular beam epitaxy (MBE). This approach is shown to provide a suitable degree of selectivity over GaAs (150:1) for conventional recess chemistries. Additionally, insertion of a 20 /spl Aring/ stop-layer does not adversely effect the electrical performance of devices as previously reported approaches based on AlAs stop-layers have. Values of maximum open channel current (I/sub MAX/) transconductance (g/sub m/), pinchoff voltage (V/sub p/) and access resistance for devices containing In/sub 0.5/Ga/sub 0.5/P stop-layers compare well with nominal process values.