Browse Prior Art Database

Method of Producing a Recessed Oxide Isolation in a Silicon Body

IP.com Disclosure Number: IPCOM000049177D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Greschner, J: AUTHOR [+4]

Abstract

The three essential features of this method are to form recessed oxide isolation (ROI) trenches with vertical sidewalls, to highly dope the bottom of these trenches, and to oxidize at high pressure and low temperature to form the ROI. The use of this method reduces the oxidation bias and thus the "bird's beak" and "bird's head".

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Method of Producing a Recessed Oxide Isolation in a Silicon Body

The three essential features of this method are to form recessed oxide isolation (ROI) trenches with vertical sidewalls, to highly dope the bottom of these trenches, and to oxidize at high pressure and low temperature to form the ROI. The use of this method reduces the oxidation bias and thus the "bird's beak" and "bird's head".

On silicon body 1, a layer 2 of SiO(2) and a layer 3 of Si(3)N(4) are formed in a known manner. On top of layer 3, a 200 nm thick siO(2) layer 4 is deposited. According to the desired ROI pattern, pattern 5 is etched into layers 4, 3 and 2 by means of known lithographic and reactive ion etching methods (Fig. 1), steep slopes in the AZ 1450J resist pattern being ensured by avoiding a postbaking step. By means of reactive ion etching in an atmosphere containing CBrF(3) or Cl(2) and Ar, ROI trenches 6 with vertical sidewalls are etched, using layer 4 as an etch mask. In the subsequent blanket ion-implantation step, the bottom areas of ROI trenches 6 are highly doped with P- or N-type impurities (Fig. 2). Outside ROI trenches 6, the ions are caught by layer 4. After layer 4 has been removed, silicon body 1 is oxidized by high pressure oxidation at about 850 degrees C to form ROI areas 8 (Fig. 3). As a result of the doping, the bottoms of the trenches oxidize up to 5 times faster than their sidewalls.

1

Page 2 of 2

2

[This page contains 3 pictures or other non-text objects]