THERMAL STABILITIES AND MICROSTRUCTURES OF TUNGSTEN COMPOUND CONTACTS ON N-GAAS FABRICATED BY LOW-ENERGY ION-BEAM-ASSISTED DEPOSITION

Abstract

A low-energy ion-beam-assisted deposition (IBAD) technique has been developed to fabricate W-Si-N Schottky contacts of enhanced thermal stabilities on n-GaAs. By implementing remote sputtering and glancing angle low-energy N+ ion irradiation, the thermal stabilities of the W-Si-N/n-GaAs Schottky contacts were enhanced to be stable up to 850-degrees-C, while keeping the Schottky barrier heights to the best values obtained with conventional sputtering. Thermal stabilities of the IBAD refractory metals/n-GaAs interfaces were investigated also for various W-Si-N compositions by examining the microstructure and Schottky diode characteristics. WSi0.3N0.4 showed the most stable Schottky contacts on n-GaAs of which the barrier height changed only 20 meV after thermal annealing between 700 and 850-degrees-C, and that is proposed to be due to the stable metallurgical microstructure compared to the element tungsten and tungsten nitride.