Browse Prior Art Database

Eliminating Boron and Arsenic Autodoping Through Reduced Pressure

IP.com Disclosure Number: IPCOM000053099D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 4 page(s) / 96K

Publishing Venue

IBM

Related People

Gaind, AK: AUTHOR [+4]

Abstract

Autodoping of boron (B) or arsenic (As) occurs inside epitaxial layers as a result of the incorporation of impurity atoms from buried layer structures. It is well known that As autodoping is significantly reduced by using a reduced pressure epitaxial deposition process. However, very little is known about the behavior of B. A significant amount of B autodoping has been found in silicon epitaxial films when deposited under reduced pressure conditions at 1150 Degrees C. Two-micron thick n type films, having 0.3-0.6 Omega cm resistivity (Rho), have been grown at a constant growth rate and at various pressures ranging from 80-760 torr. Lateral autodoping of B and As has been investigated as a function of the autodoping source area.

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 58% of the total text.

Page 1 of 4

Eliminating Boron and Arsenic Autodoping Through Reduced Pressure

Autodoping of boron (B) or arsenic (As) occurs inside epitaxial layers as a result of the incorporation of impurity atoms from buried layer structures. It is well known that As autodoping is significantly reduced by using a reduced pressure epitaxial deposition process. However, very little is known about the behavior of
B. A significant amount of B autodoping has been found in silicon epitaxial films when deposited under reduced pressure conditions at 1150 Degrees C. Two- micron thick n type films, having 0.3-0.6 Omega cm resistivity (Rho), have been grown at a constant growth rate and at various pressures ranging from 80-760 torr. Lateral autodoping of B and As has been investigated as a function of the autodoping source area. The source area has been changed by uniformly loading various amounts of blanket B- or As-diffused wafers in the reactor.

Epitaxial sheet Rho (Rs) has been measured on monitor wafers containing nine diffused squares of the source being investigated. Fig. 1 shows that both B and As autodoping increase with increasing source area. The incorporation of B in an n type epitaxial layer causes the Rs to increase, indicating strong autodoping of B at 80 torr. Thus, B autodoping increases with decreasing pressure, whereas As autodoping increases with increasing pressure. Similar observations have been confirmed by a spreading resistance probe measurement of lateral autodoping adjace...