Plasma-Enhanced Atomic Layer Deposition Processed SiO2 Gate Insulating Layer for High Mobility Top-Gate Structured Oxide Thin-Film Transistors

SiO
₂
processed by plasma-enhanced atomic layer deposition (PEALD) was applied as a gate insulator (GI) to the top gate high mobility InZnO (IZO) thin-film transistor (TFT). In as-fabricated devices, while IZO TFTs with GI processed by PEALD shows high ON/OFF ratio characteristics, the devices with GI deposited by plasma-enhanced chemical vapor deposition showed the conductive characteristics. From the secondary ion mass spectroscopy analysis, it is inferred that PEALD processed SiO
₂
generates fewer free electron donating elements in the active layer. The IZO TFT with PEALD processed GI exhibits a high-field effect mobility of 32.9 cm
²
/V · s, VON of -0.3 V, and Δ V
_ON
of 0.56 V under positive bias temperature stress (1 MV/cm, 60°C, 3600 s) after being subject to thermal annealing at 350°C.