System and method for substrate wafer back side and edge cross section seals
Systems and methods for substrate wafer back side and edge cross section seals. In accordance with a first method embodiment, a silicon wafer of a first conductivity type is accessed. An epitaxial layer of the first conductivity type is grown on a front surface of the silicon wafer. The epitaxial layer is implanted to form a region of an opposite conductivity type. The growing and implanting are repeated to form a vertical column of the opposite conductivity type. The wafer may also be implanted to form a region of the opposite conductivity type vertically aligned with the vertical column.
1. A method of growing epitaxial silicon on a silicon wafer, said method comprising:
depositing a layer of silicon oxide on all surfaces and edges of said silicon wafer;
removing said silicon oxide from a front surface of said silicon wafer;
depositing a layer of poly silicon only on a back surface of said silicon wafer, over said silicon oxide;
growing a layer of epitaxial silicon on said front surface of said silicon wafer;
growing another layer of epitaxial silicon on said layer of epitaxial silicon; and
doping a region of said layer of epitaxial silicon prior to said growing another layer of epitial silicon.
2. A method of growing epitaxial silicon on a silicon wafer, said method comprising:
depositing a layer of silicon oxide on all surfaces and edges of said silicon wafer;
removing said silicon oxide from a front surface of said silicon wafer;
depositing a layer of poly silicon on a back surface of said silicon wafer, over said silicon oxide;
growing a layer of epitaxial silicon on said front side of said silicon wafer; and
growing another layer of epitaxial silicon on said layer of epitaxial silicon, wherein said another layer of epitaxial silicon comprises a gap characterized by an absence of epitaxial silicon.