COMPARISON OF PROPERTIES OF SOLID-PHASE EPITAXIAL SILICON-ON-SAPPHIREFILMS RECRYSTALLIZED BY RAPID THERMAL ANNEALING AND FURNACE ANNEALING

Chemically vapour deposited silicon on sapphire (SOS) films 0.25 mu m thick were implanted with Si-28(+) and recrystallized in solid phase b y furnace annealing (FA) and IR rapid thermal annealing (RTA) in our l aboratory. An improvement in crystalline quality can be obtained using both annealing procedures. After FA, it is hard to retain the intrins ic high resistivity value(10(4)-10(5) Ohm cm) observed in as-grown SOS films, so the improvement process cannot be put to practical use effe ctively. However, it is demonstrated that by properly adjusting the im plantation and RTA conditions, significant improvements in both film q uality and film autodoping can be accomplished. This work describes a modified double solid phase epitaxy process in which the intrinsic hig h resistivities of the as grown SOS films are retained. The mechanism of suppression of Al autodoping is discussed.