Method for fabricating a field-effect transistor with a self-aligned gate

A method of fabricating field-effect transistors each having a source, drain and gate electrode comprising the steps of epitaxially growing layers on a semiconductor substrate including at least a current channel followed by a non-alloyed contact to form a semiconductor wafer, depositing a metallic layer over said non-alloyed contact, masking areas on the wafer corresponding to individual field-effect transistors using photoresist material and photolithography techniques, etching the metallic layer and the epitaxially grown layers to develop mesas corresponding to individual field-effect transistors, dissolving the deposited photoresist material used to define the mesa structures, masking the wafer using photolithograhy and photoresist material to define an area in each of the remaining metallic layers at the top of each mesa for the gate electrode structure of each field-effect transistors, etching in the defined areas to remove the exposed metallic layer and the non-alloyed contact, depositing a metallic layer over the entire wafer including the defined areas to form a gate structure in each defined area, and removing the photoresist material deposited during the second masking step.