In situ-doped epitaxial silicon film growth at 250 degrees C by an ultra-clean low-energy bias sputtering

The use of ultraclean technology to produce a dramatic reduction in the processing temperature has been demonstrated for silicon epitaxy by low-energy bias sputtering. Damage-free in situ substrate surface cleaning by extremely low-energy Ar ion bombardment has been used for preparing an ultraclean wafer surface before film deposition. Concurrent bombardment of a growing film surface by low-energy Ar ions with precisely controlled energy and flux has been utilized to activate the film surface. As a result, in situ doped epitaxial silicon films with high crystal perfection have been successfully grown at temperatures as low as 250 degrees C. Perfect process-parameter control and the realization of an ultraclean processing environment and ultraclean wafer surfaces have been verified to be key factors that enable such a low-temperature high-performance process.<>