부산대학교 도서관

Ultrathin indium tin oxide (ITO) films are investigated for back-end-of-line (BEOL) compatible thin-film transistors (TFTs) by plasma-enhanced atomic layer deposition (PEALD). By optimizing the ITO channel composition and thickness and a novel post-channel annealing (PCA) process, the resulting TFT exhibits high performance ( $\boldsymbol {\mu } _{\text {FE}}\,\, \boldsymbol {=}\,\,28.3$ cm2/ $\text{V}\cdot \text{s}$ , ${V}_{\text {th}}\,\, \boldsymbol {=} -0.29$ V, SS $\boldsymbol {=}\,\,123$ mV/dec, and ${I}_{\text {ON}}/{I}_{\text {OFF}}=8.1 \times 10^{{9}}{)}$ and especially extraordinary thermal stability. The thermal treatment at 400 °C for 60 min in N2 only generates very small variations of -0.17 V and -1.4% for ${V}_{\text {th}}$ and $\boldsymbol {\mu } _{\text {FE}}$ , respectively. Moreover, the optimized device also shows excellent positive/negative bias temperature stress (PBTS/NBTS) stabilities even at 2 MV/cm and 125 °C. Furthermore, when the channel length is reduced to 60 nm, the outstanding electrical performance is demonstrated, such as an ${I}_{\text {ON}}/{I}_{\text {OFF}} \boldsymbol {\sim } 10^{{10}}$ , an ${I}_{\text {ON}}$ of $715 \boldsymbol {\mu } \text{A}/ \boldsymbol {\mu } \text{m}$ , and an ${R}_{C}$ of $0.542 \boldsymbol {\Omega } \cdot $ mm. Thus, our work provides a promising candidate for BEOL compatible transistors in monolithic 3-D integration.