Method of selectively etching silicon
US5129981A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 14, 1991 |
| Grant date | Jul 14, 1992 |
| Priority date | — |
| Expiry date | Mar 14, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/924
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a method of forming thin bodies of a semiconductor material, such as single crystalline silicon, by selectively etching away a portion of the body until a body of the desired thicknes is obtained. The body includes a p-n junction made up of adjacent regions of p-type and n-type conductivity which are immersed in a chemical etchant with the surface of the p-type region being exposed to the etchant. A time varying voltage waveform having first and second voltage levels is applied through the etchant to the p-n junction. The first voltage level causes a zero forward bias across the p-n junction and the second voltage level causes a reverse bias across the p-n junction. The p-type region is removed by the chemical etchant down to the n-type region. This essentially removes the p-n junction in the area where the p-type region is etched away and resulting current through the n-type region causes a passivating layer to form on the surface of the n-type region which stops further etching.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.