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Removal of Boron Trioxide Glass from Silicon Dioxide

IP.com Disclosure Number: IPCOM000074965D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Gaier, CE: AUTHOR [+3]

Abstract

When a boron tribromide (BBr3) deposition and reoxidation precedes a phosphorus oxychloride (POCl(3)) deposition and reoxidation in the process of fabricating integrated circuit semiconductor devices, the interaction of the boron trioxide (B(2)O(3)) rich glass with the deposition of phosphorus and formation of phosphorus pentoxide (P(2)O(5)) rich glass is such that sheet resistivity, junction depth and P(2)O(5) glass thickness is enhanced. Removal of the B(2)O(3) rich glass from the silicon dioxide (SiO(2) using P-etch prior to the POCl(3) deposition process, returns the diffused phosphorus concentration to its expected level.

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Removal of Boron Trioxide Glass from Silicon Dioxide

When a boron tribromide (BBr3) deposition and reoxidation precedes a phosphorus oxychloride (POCl(3)) deposition and reoxidation in the process of fabricating integrated circuit semiconductor devices, the interaction of the boron trioxide (B(2)O(3)) rich glass with the deposition of phosphorus and formation of phosphorus pentoxide (P(2)O(5)) rich glass is such that sheet resistivity, junction depth and P(2)O(5) glass thickness is enhanced.

Removal of the B(2)O(3) rich glass from the silicon dioxide (SiO(2) using P-etch prior to the POCl(3) deposition process, returns the diffused phosphorus concentration to its expected level.

Removal of the B(2)O(3) glass from the SiO(2) consists of a one step etching process in P-etch, which consists of 300 parts H(2)O, 10 parts HNO(3) and 15 parts HF by volume, that etches away the borosilicate glass, leaving only the SiO(2). The graph shows the relationship between the etching rates of borosilicate glass.

Silicon dioxide etches at a constant rate of 2.0 angstroms/second in P-etch, while the B(2)O(3) glass etched in P-etch increases with increased B(2)O(3) concentration. This process yields optimum B(2)O(3) glass removal pertinent to semiconductor device fabrication by: 1) Effecting complete removal of the B(2)O(3) glass.

2) Providing a slow constant 2.0 angstroms/second etch rate for

SiO(2).

3) Providing excellent control of SiO(2) thickness following

B(2)O(3) glass removal...