Etching processes for solar cell fabrication

Patent metadata

Field	Value
Publication number	US-9419166-B2
Application number	US-201514975175-A
Country	US
Kind code	B2
Filing date	Dec 18, 2015
Priority date	Sep 26, 2014
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A method of fabricating a solar cell can include forming a first dopant region over a silicon substrate and an oxide region over the first dopant region. In an embodiment, the oxide region can protect the first dopant region from a first etching process. In an embodiment, a second dopant region can be formed over the silicon substrate, where a mask can be formed to protect a first portion of the second dopant region from the first etching process. In an embodiment, the first etching process can be performed to expose portions of the silicon substrate and/or a silicon region. A second etching process can be performed to form a trench region to separate a first and second doped region of the solar cell. A third etching process can be performed to remove contaminants from the solar cell and remove any remaining portions of the oxide region.

First claim

What is claimed is:

1. A method of fabricating a solar cell, the method comprising:
forming a silicon region over the silicon substrate;
forming a first dopant region on the silicon region;
forming an oxide region on the first dopant region, wherein a first portion of the oxide region protects the first dopant region from a first etching process;
forming a second dopant region on the silicon region;
driving dopants from the first and second dopant regions to the silicon region, wherein the driving forms first and second doped regions in the silicon region;
forming a mask on a first portion of the second dopant region, wherein the mask protects the first portion of the second dopant region from the first etching process;
performing the first etching process to expose portions of the silicon region and remove a first portion of the oxide region and the mask;
performing a texturing process to form a textured region on an exposed region of the silicon substrate;
performing a second etching process to remove the oxide region and contaminants from the silicon substrate; and
performing a drying process on the silicon substrate.

2. The method of claim 1 , wherein performing the first etching process to expose portions of the silicon substrate comprises etching with at least one of hydrofluoric acid and nitric acid.

3. The method of claim 1 , wherein performing the second etching process comprises etching with at least one of hydrofluoric acid, ozone or hydrochloric acid.

4. The method of claim 1 , wherein forming the second dopant region over the silicon substrate comprises forming the second dopant region over the first dopant region, oxide region and the silicon substrate.

Assignees

• Harrington Scott
• Balu Venkatasubramani
• Staffan Westerberg
• Cousins Peter John
• Sunpower Corp

Inventors

• Harrington Scott
• Balu Venkatasubramani
• Staffan Westerberg
• Cousins Peter John

Classifications

• Y02E10/547

  Monocrystalline silicon PV cells · CPC title

• Y02E10/548

  Amorphous silicon PV cells · CPC title

• H10F10/17

  Photovoltaic cells having only PIN junction potential barriers · CPC title

• H10F10/166

  the Group IV-IV heterojunctions being heterojunctions of crystalline and amorphous materials, e.g. silicon heterojunction [SHJ] photovoltaic cells · CPC title

• H10F77/147

  Shapes of bodies · CPC title