SINGLE MASK TRENCH FRED WITH ENLARGED SCHOTTKY AREA
First Claim
1. A process for the manufacture of a trench type diode comprising the steps of:
- a) forming a field oxide layer atop the surface of a silicon die portion of a wafer and forming a nitride layer atop the field oxide;
b) opening a first plurality of spaced trenches in an active area of said die portion which have a first spacing from one another and simultaneously opening at least one trench in a termination region;
said at least one trench being spaced from an adjacent one of said plurality of trenches by a spacing greater than said first spacing;
c) etching the oxide beneath said nitride to completely remove the oxide in said active area and only partly removing the oxide in said termination area whereby the surface of the silicon in the active area is exposed; and
depositing a Schottky-forming metal atop said active area and into all of said trenches.
2 Assignments
0 Petitions
Accused Products
Abstract
A single mask process is described for making a trench type fast recovery process. The single mask defines slots in a photoresist for locally removing strips of nitride and oxide from atop silicon and for subsequently etching trenches in the silicon. A boron implant is carried out in the bottoms of the trenches to form local P/N junctions. The oxide beneath the nitride is then fully stripped in the active area and only partly stripped in the termination area in which the trenches are wider spaced than in the active area. Aluminum is then deposited atop the active area and in the trenches, but is blocked from contact with silicon in the active area by the remaining nitride layer.
9 Citations
13 Claims
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1. A process for the manufacture of a trench type diode comprising the steps of:
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a) forming a field oxide layer atop the surface of a silicon die portion of a wafer and forming a nitride layer atop the field oxide;
b) opening a first plurality of spaced trenches in an active area of said die portion which have a first spacing from one another and simultaneously opening at least one trench in a termination region;
said at least one trench being spaced from an adjacent one of said plurality of trenches by a spacing greater than said first spacing;
c) etching the oxide beneath said nitride to completely remove the oxide in said active area and only partly removing the oxide in said termination area whereby the surface of the silicon in the active area is exposed; and
depositing a Schottky-forming metal atop said active area and into all of said trenches. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification