STRUCTURAL CHARACTERIZATION OF THE INTERFACIAL REACTIONS BETWEEN PALLADIUM AND GALLIUM ARSENIDE.

X-RAY DIFFRACTION WAS PERFORMED IN SITU AT TEMPERATURES FROM 25-550 D. C STUDY THE PROCESS OF COMPOUND FORMATION AT THEINTERFACE BETWEEN EVAPORATED PD THIN FILMS (APPROXIMATELY 1000 A THICK) AND GAAS SINGLE CRYSTALS. FOR HEATING IN 1 ATM ARGON, THE INTERFACIAL REACTIONS OCCURRED AT TEMPERATURES ABOVE APPROXIMATELY 250 D. C. THE PDAS//2 PHASE WAS FOUND TO BE A SURFACE LAYER WHICH COULD BE REMOVED MECHANICALLY BY ULTRASONIC CLEANING OR BY THE USE OF AN ADHESIVE TAPE. REMOVAL OF PDAS//2 WAS INDICATED BY EX SITU X-RAY DIFFRACTION RESULTS, WHICH SHOWED THE DISAPPEARANCE OF THE PDAS//2 DIFFRACTIONPEAKS AND THE ENHANCEMENT OF THE PDGA PEAKS. FOR HEATING INVACUUM (10** - **6 TORR), THE INTERFACIAL REACTIONS OCCURRED AT TEMPERATURES ABOVE APPROXIMATELY 200 D. C.