Situation
The functional principle of a solar cell involves doping to form a positive and a negative layer. The p/n junction is usually created by diffusion. During the process, an unwanted emitter is created on the back of the cell which, if it is not separated from the front, could cause a short-circuit within the cell. Thus, the edges of the wafer or cell are isolated using either laser or etching processes. The GP ISO-TEST Waf and GP ISO-TEST Cell laboratory tools carefully check isolation resistance, offering a reliable process control.
Principle
- Two spring-loaded copper plates (CELL) or spring-loaded plastic plates with recessed spring-loaded contact pins (WAF) to create an electrical contact with both sides of the cell/wafer.
Advantages
- Edges can be measured either one at a time or simultaneously (WAF only).
Technical Data
Topic |
Description |
Samples to be measured |
- Mono- and multi-crystalline wafers - Square or pseudo square - Textured or non-textured surface - Diffused layer (n+p or p+n) - Wafers without contacts, cells with contacts - Edge-isolated |
Wafer size |
100 … 156 mm |
Measurements |
Testing of edge isolation resistance by 2-point probing |
Sample preparation |
Wafers after diffusion and edge isolation |
Measured area |
Whole wafer /cell |
Measurement time |
approx. 5 sec. per wafer |
Note: All technical details are subject to change without prior notice. Only technical specifications contained in an offer are binding.