Crystalline IGO TFTs with High Reliability under DRAM-Compatible 600 °C N2 Thermal Budgets

Abstract

High-performance crystalline IGO (c-IGO) TFTs are demonstrated for 600 ∘ C DRAM integration, where the crystalline lattice plays a critical role in preventing interfacial intermixing. In amorphous IGO TFTs, extensive Al intermixing with the adjacent Al2O3 layers inhibits channel crystallization, resulting in a degraded mobility of 25.6 cm2/Vs. Conversely, the crystalline IGO effectively suppresses Al diffusion, enabling a superior mobility of 89.9 cm2/Vs and a sharp subthreshold swing of 80 mV/decade. Furthermore, c-IGO TFT exhibits superior PBTS stability ( ΔVTH of -10 mV at 4 MV/cm, 80 ∘ C, 3600 sec), proving that channel crystallization is a robust strategy to mitigate intermixing-induced structural and electrical degradation in high-temperature DRAM fabrication processes.