on inas as well as inas facets in the approach of the invention the inas film is grown under in stable conditions slight excess of in on surface by this is meant up to about 10 excess of in over stoichiometric in preferably however the excess in is maintained as close to stoichiometry as possible to minimize defects too much in balls up causing cluster defects which adversely affect electrical properties more than stoichiometric as again quenches the in surface mobility giving clustered growth with attendant dislocations and electrical defects the process of the invention gives very high surface migration rates and avery uniform smooth over layer unfortunately if the films are grown continuously under these conditions an in excess in the film would be achieved which would also destroy the structural and electrical quality ofthe film therefore 1 4 to 2 monolayers of inas are variously deposited for time periods of a few seconds the in and as shutters are then closed to interrupt the in growth and to allow the surface to equilibrate with the recently deposited film fig2 depicts the process of the invention first smoothing the surface with as as shutter on t 1 then turning the as shutter off for a period of time to permit equilibration of as surface stoichiometry t 2 then turning the in shutter on for a period of time then turning the in shutter off.