METHOD FOR GROWING SILICON SINGLE CRYSTALS Russian patent published in 1997 - IPC

FIELD: metallurgy, electronics. SUBSTANCE: silicon single crystals are grown by pulling onto revolving seed from melt in crucible, surface of which comprises cylindrical and spherical portions arranged in succession. Method makes provision for varying rotational speed of crucible (W t), while maintaining constant rotational speed of crystal (W cr). At W cr > W t, crucible rotational speed is made to vary in the process of crystal growth depending on fact, at what crucible portion melt level is found: whether it is at cylindrical or spherical portion. As crystal is grown from cylindrical crucible portion, crucible rotational speed is increased by (0.1-0.5) r.p.m. per each centimeter of crystal length, and as crystal growth proceeds from spherical crucible portion its rotational speed is reduced by (0.15-0.45) r.p.m. Method is adaptable for growing dislocation-free silicon single crystals with uniform oxygen distribution along entire crystal length by Czokhralsky technique. EFFECT: high-quality single crystalline silicon for production of integrated circuits with high integration degree. 1 tbl, 1 dwg