Effect of Annealing Temperature on the Electrical Performance of SiZnSnO Thin Film Transistors Fabricated by Radio Frequency Magnetron Sputtering
Transactions on Electrical and Electronic Materials
Amorphous oxide thin film transistors (TFTs) were fabricated with 0.5 wt% silicon doped zinc tin oxide (a-0.5SZTO) thin film deposited by radio frequency (RF) magnetron sputtering. In order to investigate the effect of annealing treatment on the electrical properties of TFTs, a-0.5SZTO thin films were annealed at three different temperatures (300 o C, 500 o C℃ , and 700 o C) for 2 hours in a air atmosphere. The structural and electrical properties of a-0.5SZTO TFTs were measured using X-ray
... raction and a semiconductor analyzer. As annealing temperature increased from 300 o C to 500 o C, no peak was observed. This provided crystalline properties indicating that the amorphous phase was observed up to 500℃ o C. The electrical properties of a-0.5SZTO TFTs, such as the field effect mobility (μ FE ) of 24.31 cm 2 / Vs, on current (I ON ) of 2.38×10 -4 A, and subthreshold swing (S.S) of 0.59 V/decade improved with the thermal annealing treatment. This improvement was mainly due to the increased carrier concentration and decreased structural defects by rearranged atoms. However, when a-0.5SZTO TFTs were annealed at 700 o C, a crystalline peak was observed. As a result, electrical properties degraded. μ FE was 0.06 cm 2 /Vs, I ON was 5.27×10 -7 A, and S.S was 2.09 V/decade. This degradation of electrical properties was mainly due to increased interfacial and bulk trap densities of forming grain boundaries caused by the annealing treatment.