Bottom-gate poly-Si thin film transistors using XeCl excimer laser annealing and ion doping techniques

High mobility bottom-gate poly-Si thin film transistors (TFTs) have been successfully fabricated on a hard glass substrate using XeCl excimer laser annealing and ion doping techniques. The authors used an a-Si:H film which is deposited by a plasma-enhanced chemical vapor deposition (PECVD) as a precursor film, and then they crystallized the a-Si film by XeCl excimer laser annealing. The maximum field effect mobility and grain size obtained were 200 cm/sup 2//V-s (n-channel), and 250 nm, respectively. The poly-Si TFTs showed excellent transfer characteristics, and an ON/OFF current ratio of over 10/sup 6/ was obtained. Successful control of the threshold voltage within 4 V using an ion doping technique is also demonstrated.>