Methods for creating a semiconductor wafer having profiled doping and wafers and solar cell components having a profiled field, such as drift and back surface
US10770613B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 4, 2019 |
| Grant date | Sep 8, 2020 |
| Priority date | — |
| Expiry date | Sep 4, 2039 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/50
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A semiconductor wafer forms on a mold containing a dopant. The dopant dopes a melt region adjacent the mold. There, dopant concentration is higher than in the melt bulk. A wafer starts solidifying. Dopant diffuses poorly in solid semiconductor. After a wafer starts solidifying, dopant can not enter the melt. Afterwards, the concentration of dopant in the melt adjacent the wafer surface is less than what was present where the wafer began to form. New wafer regions grow from a melt region whose dopant concentration lessens over time. This establishes a dopant gradient in the wafer, with higher concentration adjacent the mold. The gradient can be tailored. A gradient gives rise to a field that can function as a drift or back surface field. Solar collectors can have open grid conductors and better optical reflectors on the back surface, made possible by the intrinsic back surface field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.