Development of self-aligned series connection for thin film solar cell using oblique deposition

Abstract

Every solar module consists of individual solar cells electrically connected in series to obtain proper power. Fortunately, thin film solar module is easy to fabricate a large size and a simple process to divide a large area format thin film solar cell into oblong strip-type small area solar cells. Laser scribing has received a great deal of attention because it provides non-contact, precision, and narrower cutting than mechanical scribing to reduce the dead zone. However, it has been hard to apply for various thin film solar cells which uses flexible substrates or substrate-type solar cells. The purpose of this work is to develop self-aligned series connection (SASC) for thin film solar cells using oblique deposition without conventional laser scribing process. Oblique deposition can enable a film deposition and isolation at the same time due to a ballistic shadowing in a high vacuum state. In order to achieve this object, oblique deposition apparatus was invented. It showed steady and reproducible deposition results as the oblique angle changes. Using this apparatus, a new integration method was fabricated. The series connection using oblique deposition has some advantages compared to conventional laser scribing process Firstly, the dead zone area which does not contribute to electricity generation can be significantly decreased from 300