Electrical Characteristics Enhancement for P-Type SnOx Thin Film Transistors with Furnace and Microwave Annealing

Since the first n-type TFT was introduced in 1962, it was made of polycrystalline cadmium sulfide (CdS) as the active layer, silicon dioxide (SiO2) and gold (Au) as the insulator electrodes. Now, n-type TFT is still the most applications in display products. In order to make display products more energy-efficient, complementary MOS circuit design is considered as a promising selection, and P-type TFT devices play an important role in it. This work focuses on how the oxygen ambient annealing process affects SnOx TFTs device electrical characteristic. In the oxygen ambient, both furnace and microwave annealing (MWA) are used to anneal P-type SnOx TFTs to realize its P-type property and enhance its electrical characteristics. The best results are reached at 300 °C, 30 min of furnace annealing and 1200 W, 100 sec of MWA. The fieldeffect mobility are 0.2596 cm2/V * s and 0.1581 cm2/V * s, threshold voltage are −2.65 V and −3.28 V, sub threshold swing are 0.485 V/decade and 0.93 V/decade, current ratio Ion/Ioff are 3.07×104 and 1.65×104, respectively. The experiment results show that both furnace annealing and MWA in oxygen ambient could effectively enhance P-type SnOx TFTs.