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Abstract— High‐performance top‐gate thin‐film transistors (TFTs) with a transparent zinc oxide (ZnO) channel have been developed. ZnO thin films used as active channels were deposited by rf magnetron sputtering. The electrical properties and thermal stability of the ZnO films are controlled by the deposition conditions. A gate insulator made of silicon nitride (SiNx) was deposited on the ZnO films by conventional P‐CVD. A novel ZnO‐TFT process based on photolithography is proposed for AMLCDs. AMLCDs having an aperture ratio and pixel density comparable to those of a‐Si:H TFT‐LCDs are driven by ZnO TFTs using the same driving scheme of conventional AMLCDs.

Abstract-Electrical properties of thin-film transistors with ZnO channels which was deposited by rf magnetron sputtering at various oxygen partial pressures [p(O 2 )] were investigated. Negative shift of turn-on voltage with "hump" was observed, and donor-like traps were generated at intermediate energy levels from conduction band when the ZnO channel was deposited at the p(O 2 ) below a critical pressure. Thermal desorption spectroscopy study revealed that the donor-like traps were generated when the ZnO film changed from O-rich to Zn-rich condition. The Zn related native defects would be possible origin of the donor-like traps generated intermediate energy levels in the ZnO TFTs.

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High‐performance top‐gate ZnO thin‐film transistors (TFTs) for AM‐LCDs have been developed. Sputtered ZnO was used as an active channel and silicon nitride (SiNx) deposited by plasma enhanced chemical vapor deposition (P‐CVD) was used as a gate insulator. Field effect mobility and threshold voltage of the ZnO‐TFT are 50.3 cm2/V⋅sec and 1.1 V, respectively. We first demonstrated a 1.46″ diagonal AM‐LCD driven by ZnO‐TFTs.