Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea.
Department of Chemistry, Chungnam National University , Daejeon 34134, Korea.
ACS Appl Mater Interfaces. 2017 Jul 19;9(28):23934-23940. doi: 10.1021/acsami.7b04985. Epub 2017 Jul 5.
Indium gallium oxide (IGO) thin films were deposited via atomic layer deposition (ALD) using [1,1,1-trimethyl-N-(trimethylsilyl)silanaminato]indium (InCA-1) and trimethylgallium (TMGa) as indium and gallium precursors, respectively, and hydrogen peroxide as the reactant. To clearly understand the mechanism of multicomponent ALD growth of oxide semiconductor materials, several variations in the precursor-reactant deposition cycles were evaluated. Gallium could be doped into the oxide film at 200 °C when accompanied by an InCA-1 pulse, and no growth of gallium oxide was observed without the simultaneous deposition of indium oxide. Density functional theory calculations for the initial adsorption of the precursors revealed that chemisorption of TMGa was kinetically hindered on hydroxylated SiO but was spontaneous on a hydroxylated InO surface. Moreover, the atomic composition and electrical characteristics, such as carrier concentration and resistivity, of the ALD-IGO film were controllable by adjusting the deposition supercycles, composed of InO and GaO subcycles. Thus, ALD-IGO could be employed to fabricate active layers for thin-film transistors to realize an optimum mobility of 9.45 cm/(V s), a threshold voltage of -1.57 V, and a subthreshold slope of 0.26 V/decade.
氧化铟镓 (IGO) 薄膜采用原子层沉积 (ALD) 通过[1,1,1-三甲基-N-(三甲基甲硅烷基)硅烷氨基]铟 (InCA-1) 和三甲基镓 (TMGa) 分别作为铟和镓前体，以及过氧化氢作为反应物沉积而成。为了清楚地了解氧化物半导体材料多组分 ALD 生长的机理，评估了前体-反应物沉积循环的几种变化。当与 InCA-1 脉冲一起时，可以在 200°C 时将镓掺杂到氧化物薄膜中，并且如果没有同时沉积氧化铟，则不会观察到氧化镓的生长。对于前体的初始吸附的密度泛函理论计算表明，TMGa 的化学吸附在羟基化的 SiO 上受到动力学阻碍，但在羟基化的 InO 表面上是自发的。此外，ALD-IGO 薄膜的原子组成和电特性，例如载流子浓度和电阻率，可以通过调整由 InO 和 GaO 亚循环组成的沉积超循环来控制。因此，ALD-IGO 可用于制造薄膜晶体管的有源层，以实现 9.45 cm/（V s）的最佳迁移率、-1.57 V 的阈值电压和 0.26 V/decade 的亚阈值斜率。
