ALD Al2O3 gate dielectric on the reduction of interface trap density and the enhanced photo-electric performance of IGO TFT.

Abstract

The amorphous indium gallium oxide thin film transistor was fabricated using a cosputtering method. Two samples with different gate dielectric layers were used as follows: sample A with a SiO2 dielectric layer; and sample B with an Al2O3 dielectric layer. The influence of the gate dielectrics on the electric and photo performance has been investigated. Atomic layer deposition deposited the dense film with low interface trapping density and effectively increased drain current. Therefore, sample B exhibited optimal parameters, with an Ion/Ioff ratio of 7.39 × 107, the subthreshold swing of 0.096 V dec−1, and μFE of 5.36 cm2 V−1 s−1. For ultraviolet (UV) detection, the UV-to-visible rejection ratio of the device was 3 × 105, and the photoresponsivity was 0.38 A W−1 at the VGS of −5 V.