Grain Growth Mechanism of Heavily Phosphorus‐Implanted Polycrystalline Silicon

Grain growth phenomena of heavi ly phosphorus- implanted polycrystal-l ine silicon films owing to high temperature annealing are investigated by transmission electron microscope. Phosphorus doping in excess of 4 • 1020 cm- ~ is found to enhance grain growth. This growth is broken down into pr imary and secondary recrystall ization. Isochronal annealing reveals the activation energies for these as 2.4 and 1.0 eV, respectively. The driving force of the pr imary recrystal l ization is found to be the interface energy. There-fore, the elementary process behind the primary, recrystal l ization is attr ibuted to sil icon diffusion across the grain boundary region. Polycrystal l ine sil icon (poly Si) is commonly used as gate materials of MOS LSI 's (1). In particular, re-cent progress in fine pattern l i thographic technology has made it indispensable to control the pattern defi-nition as well as to lower the resist ivity of the mate-