JPS5583271A - Semiconductor device - Google Patents

Abstract

PURPOSE: To increase the current capacity of a semiconductor device by forming a p-type buried layer forming a zener diode particularly in high impurity density to thereby reduce dynamic resistance thereof to thus reduce noise thereat.

CONSTITUTION: An oxide film 21 is coated on a p-type silicon substrate 20, openings are perforated at the film 21, thin oxide films 22 are formed thereat, and n-type impurity ion is implanted through the film 22 to thereby form an n^--type region 23. Then, the film 22 is modified into an oxide film 24, openings are perforated at the region 23, a BSG film 25 is coated on the entire surface thereof, heat treated, and the impurity is diffused to thereby form a p⁺-type region 26 in the region 23. Then, the film 25 is removed, an n-type layer 27 is epitaxially grown on the entire surface thereof, an oxide film 28 is coated thereon, the BSG film 29 is again coated thereon, heat treated to thereby diffuse the impurity into the region 26 to thereby form two p⁺-type regions 30 and 31 reaching the region 26. Then, the film 29 is removed, an oxide film 32 is newly formed on the layer 27, a BSG film 29' is coated thereon, openings are perforated thereat, n-type impurity is adhered thereto to thereby form an n⁺-type region 34 not superimposed with the region 31 being larger than the high density buried region 30.

COPYRIGHT: (C)1980,JPO&Japio