Browse Prior Art Database

Control of Silicon Glass Interface Potential

IP.com Disclosure Number: IPCOM000095390D
Original Publication Date: 1965-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Sunners, B: AUTHOR [+3]

Abstract

When semiconductor devices are provided with an overlying adherent coating of oxide or glass, the coating normally induces a shift in potential at the interface in either a P or an N direction. For example, a thin layer of silicon oxide on a silicon device tends to produce an N-type interface layer on the silicon. When glass coatings are sedimented and fired on silicon, certain glasses shift the interface potential in an N-direction. Certain other glasses shift the interface potential in the P-direction. The interface potential shift can have a detrimental effect on the device operation.

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Control of Silicon Glass Interface Potential

When semiconductor devices are provided with an overlying adherent coating of oxide or glass, the coating normally induces a shift in potential at the interface in either a P or an N direction. For example, a thin layer of silicon oxide on a silicon device tends to produce an N-type interface layer on the silicon. When glass coatings are sedimented and fired on silicon, certain glasses shift the interface potential in an N-direction. Certain other glasses shift the interface potential in the P-direction. The interface potential shift can have a detrimental effect on the device operation.

The direction of the interface potential shift resulting from a lead-alumina- borosilicate glass coating can be predicted from a consideration of the nature of, proportions of, and heats of formation of, the component oxides of the glass.

To predict the interface potential shift, the overall heat of formation of the glass is calculated by adding the products of the mole percent and respective heat of formation of each of the component oxides. If the overall heat of formation of the glass is below a value of 175 Kcal/mol, the interfacial potential is shifted in the N-direction. If the overall heat of formation is above a value of 190 Kcal/mol, the interfacial potential is shifted in the P-direction. In general, for heats of formation between 175 Kcal/mol and 190 Kcal/mol, the inter-facial potential shift can be in either direction, but...