US 2012/0258561 A1 · Low-Temperature Method for Forming Amorphous Semiconductor Layers

Abstract

In embodiments of the present invention an undoped amorphous, nanocrystalline or microcrystalline semiconductor layer and a heavily doped amorphous, nanocrystalline, or microcrystalline semiconductor layer are formed on a monocrystalline silicon lamina. The lamina is the base region of a photovoltaic cell, while the amorphous, nanocrystalline or monocrystalline layers serve to passivate the surface of the lamina, reducing recombination at this surface. In embodiments, the heavily doped layer additionally serves as either the emitter of the cell or to provide electrical contact to the base layer. The undoped and heavily doped layers are deposited at low temperature, for example about 150 degrees C. or less with hydrogen dilution. This low temperature allows use of low-temperature materials and methods, while increased hydrogen dilution improves film quality and/or conductivity.

Claims27

Dependent claims

A method for forming a device, the method comprising:

providing a monocrystalline semiconductor lamina having a first surface and a second surface opposite the first;
depositing a first undoped amorphous, nanocrystalline, or microcrystalline semiconductor layer on and in contact with the second surface of the lamina by PECVD while flowing a precursor gas, the first undoped layer having a thickness less than about 100 angstroms;
depositing a second doped amorphous, nanocrystalline, or microcrystalline semiconductor layer on and in contact with the first undoped layer by PECVD while flowing the precursor gas, the second doped layer having a thickness less than about 300 angstroms,
wherein, during the step of depositing the first undoped layer and the step of depositing the second doped layer, deposition temperature is less than about 150 degrees C. and a ratio of hydrogen to the precursor gas is at least 1:1;
and
wherein the lamina, the first undoped layer, and the second doped layer are suitable for use in a photovoltaic cell.

3 more elements

Dependencies are inferred from the claim text.

Low-Temperature Method for Forming Amorphous Semiconductor Layers

Life of this patent

Low-Temperature Method for Forming Amorphous Semiconductor Layers

Life of this patent

Abstract

Claims27