EFFECTS OF SI(100) TILTING ANGLE AND PRELAYER CONDITIONS ON GAAS SI HETEROSTRUCTURES/

Vicinal Si(100) substrates with tilting angles of 0-9 degrees toward [ 01-1] have been investigated for the molecular beam epitaxy of GaAs-on -Si heterostructures, The major difference between tilting angles was found to be the GaAs(100) orientation which can be achieved on each an gle; for the 7.5 degrees it was too difficult and for 9.0 degrees it w as impossible to obtain GaAs [011] parallel (instead of perpendicular) to the Si [01-1] tilting direction, while this was reproducibly attai nable for the 1.5-6.0 degrees range, using pre-exposure of Si to As at 400 degrees C, Smooth GaAs surfaces for angles above 1.5 degrees can only be obtained for this GaAs orientation and thus the useful angle r ange is limited between 1.5-6.0 degrees, Furthermore, material and dev ice characterization results promote the choice of the 4.5 degrees til ting angle from the above range slightly.