Plasma Enhanced atomic layer deposited amorphous gallium oxide thin films using novel trimethyl[N-(2-methoxyethyl)-2-methylpropan-2-amine]gallium

Abstract

We developed a novel liquid type Ga precursor, trimethyl [N-(2-methoxyethyl)-2-methylpropan-2-amine]gallium (TMGON, Ga(CH3)-3 [CH3OCH2CH2NHtBu]) with a reasonable vapor pressure (0.5 Torr at 54 °C), to deposit GaOx via plasma-enhanced atomic layer deposition (PEALD) using a mixture gas of Ar/O2 as a reactant at low temperature. In this study, the growth per cycle (GPC) was 1.0 Å/cycle at deposition temperatures between 100 °C and 250 °C. As the deposition temperature increased, the amount of remaining carbon decreased. The ratio of Ga/O came close to the ideal ratio of 2:3, and the optical band gap increased, respectively. In addition, all films had amorphous phases and low surface roughness. The GaOx films also exhibited acceptable insulator properties, with a leakage current of 3.2⨯10−9 A/cm2 at 0.5 MV/cm and breakdown fields of 1.52 MV/cm. These results demonstrate that TMGON is a promising ALD precursor for the deposition of GaOx as well as a multi-component oxide layer including Ga, due to a high GPC and good film properties.