Method of purifying substrate from unwanted heavy metals
US5454885A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1993 |
| Grant date | Oct 3, 1995 |
| Priority date | — |
| Expiry date | Dec 21, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/064
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A typical source of cadmium and tellurium is as a by-product of copper mining. Although attempts are made to remove impurities such as copper prior to commercially supplying them for forming material like cadmium telluride, cadmium zinc telluride and cadmium telluride selenide for use as a substrate to support electronic circuitry, processing during formation of the circuitry causes the impurities from the substrate to segregate into the circuitry, resulting in unacceptable electrical performance of the circuitry. A method for purifying the substrate prior to circuitry formation includes forming a sacrificial layer of mercury telluride or mercury cadmium telluride on the substrate, annealing the combination at elevated temperature with an overpressure of mercury and removing the sacrificial layer along with a contiguous portion of the substrate, if desired. The sacrificial layer may be formed by vapor phase type processes or even by liquid phase epitaxy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.