A multi process reactor for low temperature TFT fabrication

A single chamber multi-process reactor has been developed specifically for Thin Film Transistor (TFT) technology. A variety of processes can be performed sequentially in the system with minimum delay between process steps. Processes available at the moment include CVD silicon, plasma enhanced silicon nitride deposition and plasma etching/substrate cleaning. The layers produced to date and the processes available with this machine have been characterised. The individual processes have yielded results comparable to those of single step reactors. All processes developed with this reactor have been limited to 620°C to ensure compatibility with Corning 7133 glass substrates. Polysilicon TFT´s, with silicon nitride gate dielectrics, have been fabricated with mobilities of 30 cm²/Vsec and on/off current ratios of >10⁶. The system is best exploited when multi-layer structures are required with minimal contamination. SIMS results of the interface properties are shown for layers deposited sequentially