Browse Prior Art Database

Complementary Bipolar Process

IP.com Disclosure Number: IPCOM000047573D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Bhatia, HS: AUTHOR [+4]

Abstract

The importance of complementary bipolar devices is well known. A process is described which produces complementary bipolar devices having a high performance lateral PNP device. The process starts with forming dielectric isolation regions 10 to isolated regions of silicon from other such regions at a major surface of a semiconductor wafer. There are two associated silicon regions: left-hand side one designated to have an NPN device formed therein and the right-hand side one designated to have a PNP device formed therein for the complementary bipolar structure. Silicon dioxide layer 12 and silicon nitride layer 14 are deposited thereover, as seen in Fig. 1.

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Complementary Bipolar Process

The importance of complementary bipolar devices is well known. A process is described which produces complementary bipolar devices having a high performance lateral PNP device. The process starts with forming dielectric isolation regions 10 to isolated regions of silicon from other such regions at a major surface of a semiconductor wafer. There are two associated silicon regions: left-hand side one designated to have an NPN device formed therein and the right-hand side one designated to have a PNP device formed therein for the complementary bipolar structure. Silicon dioxide layer 12 and silicon nitride layer 14 are deposited thereover, as seen in Fig. 1. Using lithography and etching techniques the designated contact areas are opened for the emitter and collector for PNP and base areas for NPN through the silicon nitride layer 14 to silicon dioxide layer 12, as shown in Fig. 2. The silicon structure is coated with about one micron of resist. The resist (not shown) is used as a block-off mask, for the NPN emitter area. The layer 12 is removed where it is unprotected by resist or layer 14 by conventional etching. Then about 0.5-0.8 micrometer of silicon is removed. The resist is removed to produce the Fig. 3. structure. About 30 to 50 nanometers of silicon dioxide 16 is grown upon the exposed silicon. Then about 30 to 50 nanometers of silicon nitride is deposited thereover. The structure is anisotropically etched, to remove the horizontal portions of the layer 18 while leaving the vertical portions, as seen in Fig. 4. A layer 20 of silicon dioxide is grown upon the exposed silicon at the bottom of the grooves by thermal oxidation. The silicon nitride 18 and 30 to 50 nanometers of silicon dioxide layer 16 are removed by wet chemical etching. The silicon dioxide layer 12 in...