Polycrystalline Silicon Ribbons Made by Rapid Quenching Methods

Abstract

Polycrystalline silicon ribbons were prepared by Roller Quenching Methods. Ribbons obtained were produced at an ultra high speed about 20 m/sec, and the size was 20 µm to 200 µm in thickness and 1 mm to 50 mm in width. Microscopic observations of etched ribbon surface showed that the average grain size were 20 µm to 30 µm. Cross sectional view showed the ribbons in columnar grain structure. Any unwanted impurity was undetectable by an Auger analysis except very thin oxygenated layer on the surface of ribbons. The active carrier concentration of the ribbons was nearly the same with the doped impurity concentration from 1014/cm3 to 1020/cm3, and the Hall mobility parallel to the ribbon axis and perpendicular to the ribbon plane was 1 to 150 cm2· V-1· sec-1 and 700 cm2· V-1· sec-1, respectively. A solar cell using the present ribbon was made by a thermal diffusion method. The satisfactory diode characteristics and the conversion efficiency of about 5% were obtained.