Etching Semiconductor Absorber Layer for PV Adhesion

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Solution Overview

Problem

Conventional photovoltaic (PV) devices with smooth semiconductor absorber layers face issues with adhesion of back contacts, doping uniformity, and grain growth, leading to reduced efficiency and reliability due to low surface roughness of the back surface.

Innovation Solution

Etching the semiconductor absorber layer to increase its surface roughness, followed by heat treatment with a chloride compound to enhance adhesion and promote uniform doping and grain growth, thereby improving the efficiency and reliability of the PV device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the semiconductor absorber layer is formed with a smooth back surface, then the deposition process is simpler, but the adhesion of the back contact to the absorber layer is poor

Engineering Contradiction:

Improvedeposition process simplicityVSAvoidback contact adhesion

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies a preliminary etching treatment to the back surface of the absorber layer before back contact deposition. This etching step creates the desired rough surface morphology in advance, ensuring good adhesion properties before the back contact is applied, thus resolving the contradiction between manufacturing simplicity and adhesion reliability.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If the back surface of the absorber layer is smooth, then the surface is easier to manufacture, but the grain growth and doping uniformity are inhibited

Engineering Contradiction:

Improvesurface formation easeVSAvoidgrain growth uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The etching step is performed as a preliminary action before the heat treatment process. By pre-roughening the surface, the subsequent heat treatment can proceed more effectively to achieve uniform grain growth and doping, resolving the contradiction between ease of surface formation and manufacturing precision of grain structure.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The increased surface roughness of the absorber layer improves adhesion to the back contact, enhances porosity and doping uniformity, and boosts electrical output by promoting larger grain size and reduced electrical defects, resulting in improved efficiency and reliability of the PV device.

Implementation Method 1

at least a portion of a back surface of the semiconductor absorber layer is etched

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 2

heat treatment with a chloride compound to enhance adhesion and promote uniform doping and grain growth

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

A PV device converts the energy of sunlight directly into electricity by the photovoltaic effect

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS9397238B2Method of etching a semiconductor layer of a photovoltaic device

Publication Date: 2016.07.19 JPMORGAN CHASE BANK NA

AI summary

A method and apparatus provide for a roughened back surface of a semiconductor absorber layer of a photovoltaic device to improve adhesion. The roughened back surface may be achieved through an etching process.