Remote Plasma and Thermal ALD of Al2O3 for Trench Capacitor Applications

Abstract

The remote plasma ALD process of Al2O3 from Al(CH3)3 and O2 plasma was characterized and compared to the well established thermal ALD process of Al2O3 employing H2O as the oxidant. The growth per cycle, saturation of the surface reactions and material properties were investigated for substrate temperatures between 25 and 300 {degree sign}C. It was demonstrated that high-quality films can be obtained for substrate temperatures above 100 {degree sign}C. For these temperatures the mass densities of the remote plasma ALD films are slightly higher than those of the thermally deposited films. Remote plasma ALD also yields fair material properties below 100 {degree sign}C at a relatively high growth per cycle and short cycle times. With remote plasma ALD conformal films were achieved in high-aspect ratio structures. Together with the first results on electrical characterization, it was shown that the Al2O3 deposited is promising for the application in metal-oxide-semiconductor trench capacitors.