A Novel Amorphous InGaZnO Thin Film Transistor Structure without Source/Drain Layer Deposition

In this paper, new structured amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) without conventional source/drain (S/D) layer deposition were introduced. The S/D layers were formed in a-IGZO channel layer by hydrogen (H 2 ) plasma treatments. As the increased plasma treatment time, the resistivity of plasma treated a-IGZO as S/D decreased drastically from 10 4 to 4.8 ×10 -3 Ω cm due to the carrier generation by plasma treatment for 240 s. The carrier concentration mechanism of the H 2 plasma treated sample could be attributed to the preferential sputtering of oxygen by H 2 bombardment due to formation of an oxygen vacancy and removal of adsorbed O 2 . The new proposed TFTs exhibited a field-effect mobility of 7.14 cm 2 V -1 s -1 , an on/off ratio of 7.95 ×10 6 , a threshold voltage of 0.94 V, and a subthreshold swing of 1.06 V/decade. These results demonstrated the possibility of low cost TFT process because S/D electrode deposition was unnecessary.