Thermal treatment of silicon wafers useful for photovoltaic applications

Patent metadata

Field	Value
Publication number	US-9105786-B2
Application number	US-201213446450-A
Country	US
Kind code	B2
Filing date	Apr 13, 2012
Priority date	Apr 18, 2011
Publication date	Aug 11, 2015
Grant date	Aug 11, 2015

Abstract

Efficiency of silicon photovoltaic solar cells is increased by an annealing process for immobilizing oxygen formed in Czochralski-grown silicon. The annealing process includes a short anneal in a rapid thermal annealing chamber at a high temperature, for example, greater than 1150° C. in an oxygen-containing ambient. More preferably, the wafer is rapidly cooled to less than 950° C. without an intermediate temperature hold, at which temperature oxygen does not nucleate and/or precipitate. Subsequent processing to form a photovoltaic structure is typically performed at relatively low temperatures of less than 1000° C. or even 875° C.

First claim

What is claimed is:

1. A process for forming a photovoltaic solar wafer, comprising the steps of:
growing a silicon ingot by the Czochralski process;
mechanically forming a plurality of silicon wafers from the ingot;
annealing at least one of the wafers at an annealing temperature of greater than 1150° C. in an oxygen-containing ambient for a time of between 1 and 60 seconds; and
then fabricating a photovoltaic solar cell structure including a semiconductor junction in the a…

Assignees

• Deluca John P
• Cisco Tech Inc

Inventors

• Deluca John P

Classifications

• H10F71/128

  Electricity · mapped topic

• H10F10/14 Primary

  Electricity · mapped topic

• H01L31/1864

  Electricity · mapped topic

• Y02E10/547

  Cross-Sectional Technologies · mapped topic

• H01L31/068 Primary

  Electricity · mapped topic