Microzone Recrystallization of InSb Thin Films for Hall Effect Magnetic Heads

Abstract

A new processing method is proposed for fabricating indium antimonide thin film Hall elements on ferrite substrates applicable to high singal-to-noise ratio Hall effect magnetic heads. The procedures include (1) coating the substrate with a thin glass layer containing 12 mol% alumina, then evaporating InSb film on it, (2) microzone-recrystallization of the film in a helium atmosphere containing ∼300 ppm oxygen, and (3) lapping the film to obtain a desired thickness (2 µm) and smooth surface. The film thus formed, having the grain size of ∼3 mm×0.5 mm and dislocation density of ∼107 cm-2, shows electron mobility of 60,000 cm2/Vs, Hall coefficient of 350 cm3/C at 300 K (comparable to those of the purest single crystal) and remarkably low current noise in the audio frequency range.