Improvement of polycrystalline silicon thin-film transistors with nickel-titanium oxide by sol-gel spin-coating and nitrogen implantation

Polycrystalline silicon thin-film transistors (poly-Si TFTs) have attracted much attention because of the different applications, such as driving circuits of the active matrix liquid crystal displays (AM-LCDs) and those of the active matrix organic light emitting diode displays (AM-OLEDs) [1, 2]. Nickel-titanium oxide (NiTiO₃) deposited by physical vapor deposition was introduced to be a high dielectric constant material [3]. It has been reported that NiTiO₃ could be the gate dielectric of poly-Si TFTs by sol-gel spin-coating previously [4]. However, to improve the electrical performance and reliability of poly-Si TFTs, defect passivation such as hydrogen plasma treatment to create Si-H bonds is usually needed. Unfortunately, the weak Si-H bonds tend to degrade device reliability under long-term electrical operation. In this paper, high performance N-type poly-Si TFTs is demonstrated by taking advantage of the high-κ NiTiO₃ gate dielectric by sol-gel spin-coating and nitrogen ion implantation technique.