11:30 AM - 11:45 AM
▲ [16a-502-10] Effect of Dimethylaluminum Hydride as Al2O3 Precursor on the Characteristics of a-InGaZnO Thin-Film Transistors
Keywords:a-IGZO TFT, DMAH, alumina
Passivation layers are elements added to improve the stability as well as the photoresponse of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) [1]. One promising technique used to deposit these layers is through atomic layer deposition (ALD) owing to its excellent conformity and simple yet accurate thickness control mechanism through layer-by-layer deposition [2]. In this study, we explored dimethylaluminum hydride (DMAH) as a new Al2O3 precursor utilizing its higher deposition rate and fewer methyl groups compared to a well-used precursor trimethylaluminum (TMA). Specifically, the effect of DMAH on the characteristics of Al2O3-passivated a-IGZO TFTs was investigated.
Bottom gate top contact a-IGZO TFTs were fabricated by sputtering the a-IGZO channel material and Mo/Pt electrodes. After atmospheric (N2:O2 = 4:1) (AT) annealing, Al2O3 passivation layers were deposited through thermal- or plasma-ALD using trimethylaluminum (TMA) or DMAH as precursor. Finally, the passivated a-IGZO TFTs were annealed at different post-annealing environments, namely AT, N2, and O2.
After testing, only the TFTs passivated using plasma-ALD exhibited switching behavior as shown in Fig. 1. From the TFT characteristics obtained, it was observed that a-IGZO TFTs passivated using DMAH as prescursor resulted to higher carrier mobilities, Von (Vgs at 1 nA) closer to 0 V and lower subthreshold swing (S) compared to TFTs passivated using TMA. Furthermore, the O2-annealed a-IGZO TFT passivated using DMAH exhibited the best set of transfer characteristics as shown in Table 1 as well as the highest stability against positive and negative bias stresses. These results show that DMAH is a promising precursor for Al2O3 passivation.
Bottom gate top contact a-IGZO TFTs were fabricated by sputtering the a-IGZO channel material and Mo/Pt electrodes. After atmospheric (N2:O2 = 4:1) (AT) annealing, Al2O3 passivation layers were deposited through thermal- or plasma-ALD using trimethylaluminum (TMA) or DMAH as precursor. Finally, the passivated a-IGZO TFTs were annealed at different post-annealing environments, namely AT, N2, and O2.
After testing, only the TFTs passivated using plasma-ALD exhibited switching behavior as shown in Fig. 1. From the TFT characteristics obtained, it was observed that a-IGZO TFTs passivated using DMAH as prescursor resulted to higher carrier mobilities, Von (Vgs at 1 nA) closer to 0 V and lower subthreshold swing (S) compared to TFTs passivated using TMA. Furthermore, the O2-annealed a-IGZO TFT passivated using DMAH exhibited the best set of transfer characteristics as shown in Table 1 as well as the highest stability against positive and negative bias stresses. These results show that DMAH is a promising precursor for Al2O3 passivation.