Novel Plasma Reactor Principle for Amorphous Silicon Deposition enabling High Efficiency Energy Conversion

Solar modules have reached the point of grid parity. Energy produced from sunlight is as cost efficient as traditional techniques. The quest for more efficiency and higher energy output per area is still ongoing and will continue.

A key technology to manufacture solar cells is Plasma Enhanced Chemical Vapor Deposition (PECVD). The requirements for various types of films are becoming more stringent as the need to drive up cell efficiency continues to increase.

This paper describes a novel parallel plate plasma reactor principle to deposit amorphous Si layers in particularly high quality with regards to thickness, uniformity and density. The process offers enhanced carrier lifetime properties which in turn enable increased solar cell efficiency.

The work describes the principle of the parallel plate reactor system (aka S-cube) and discusses the data obtained during the development. The capabilities of the reactor system in the context of HIT (Heterojunction Intrinsic Thin Layer) solar cell processing are being explored. The paper illuminates the need for doped layers and illustrates the capabilities and challenges when depositing p-type, n-type and intrinsic amorphous Silicon.

The work summarizes today’s state of the technology and proposes a roadmap for future enhancements and improvements as they are already foreseeable.