| 摘要 |
THE PRESENT INVENTION RELATES TO SINGLE CRYSTAL SILICON, IN INGOT (10) OR WAFER FORM, WHICH CONTAINS AN AXIALLY SYMMETRIC REGION (6) WHICH IS FREE OF AGGLOMERATED INTRINSIC POINT DEFECTS, AND A PROCESS FOR THE PREPARATION THEREOF. THE PROCESS COMPRISES CONTROLLING GROWTH CONDITIONS, SUCH AS GROWTH VELOCITY, V, INSTANTANEOUS AXIAL TEMPERATURE GRADIENT, GO, AND THE COOLING RATE, WITHIN A RANGE OF TEMPERATURES AT WHICH SILICON SELF-INTERSTITIALS ARE MOBILE, IN ORDER TO PREVENT THE FORMATION OF THESE AGGLOMERATED DEFECTS. IN INGOT FORM, THE AXIALLY SYMMETRIC REGION (6) HAS A WIDTH (22), AS MEASURED FROM THE CIRCUMFERENTIAL EDGE (20) OF THE INGOT RADIALLY TOWARD THE CENTRAL AXIS (12), WHICH IS AT LEAST ABOUT 30% THE LENGTH OF THE RADIUS (4) OF THE INGOT (10). THE AXIALLY SYMMETRIC REGION (6) ADDITIONALLY HAS A LENGTH (24), AS MEASURED ALONG THE CENTRAL AXIS (12), WHICH IS AT LEAST ABOUT 20% THE LENGTH (26) OF THE CONSTANT DIAMETER PORTION OF THE INGOT (10). |
