ELECTRONIC GAAS-ON-SILICON MATERIAL FOR ADVANCED HIGH-SPEED OPTOELECTRONIC DEVICES

THE SUCCESSFUL GROWTH OF GAAS ON SILICON SUBSTRATES USING DOUBLE SELECTIVE LIQUID EPITAXIAL (DSLE) PROCESS HAS RECENTLY BEEN ACCOMPLISHED. THESE RESULTS SET THE STAGE FOR THE DEVELOPMENT OF AN EXTREMELY USEFUL MATERIAL--LARGE PLANAR WAFERS OF SMOOTH GAAS ON SILICON. DOUBLE SELECTIVE LIQUID PHASE EPITAXY COULD SIGNIFICANTLY REDUCE THE PROBLEMS CAUSED BY LATTICE MISMATCH AND DIFFERENTIAL THERMAL EXPANSION BY REDUCING THE AREA OF CONTACT BETWEEN ADJACENT SEMICONDUCTOR LAYERS TO SMALL NUCLEATION VIAS ONLY MICRONS IN DIAMETER. SMOOTH, PLANAR LOW-DISLOCATION GALLIUM ARSENIDE OVERGROWTH IS BEING PREPARED BASED ON THE DSLE PROCESS BY CONTROLLING THE THERMOCHEMISTRY AND KINETICS OF THE GAAS OVERLAYER GROWTH TO ELIMINATEFACETING. LIQUID PHASE EPITAXY IS EXPECTED TO RESULT IN LOWER RESIDUAL BACKGROUND IMPURITY LEVELS THAN OTHER GROWTH TECHNIQUES. STABLE SEMI-INSULATING GAAS LAYERS ARE BEING PREPARED BY LOW LEVEL DOPING WITH A DEEP LEVEL ACCEPTOR. MATERIAL QUALITY AND UNIFORMITY ARE BEING DEMONSTRATED BY FABRICATING SIMPLE MAJORITY AND MINORITY CARRIER DEVICES. A FEASIBILITY STUDY AND EQUIPMENT DESIGN FOR 16 SQUARE INCH GAAS-ON-SILICON WAFERS IS BEING COMPLETED.