Electron beam source molecular beam epitaxial growth of analog graded Al sub x Ga sub (1-x) As ballistic transistors.

A new method has been developed for the growth of graded band- gap Al sub x Ga sub (1-x) As alloys by molecular beam epitaxy which is based upon electron beam evaporation of the Group III elements. The metal beam fluxes are measured and feedback controlled using a modulated ion gauge sensor. The system is computer controlled which allows precise programming of the Ga and Al evaporation rates. The large dynamic response of the metal sources enables the growth of variable band-gap III-V alloys with arbitrary composition profiles. This new technique is demonstrated in the synthesis of Al sub x Ga sub (1-X) As unipolar ballistic electron transistors.