Effect of Process Pressure on Atomic Layer Deposition of Al2O3

Abstract

Aluminum oxide (Al 2 O 3 ) thin films have been prepared by the atomic layer deposition (ALD) using trimethylaluminum (TMA) and ozone (O 3 ) as precursors. The process pressure was varied from 200-1000 mTorr at lower deposition temperature of 320 o C and compared its effects on the properties with increasing deposition temperature to 460 o C. The film growth rate and the film properties of thickness uniformity, impurity incorporation and the step coverage in high aspect ratio features were characterized. It was found that the deposition temperature decrease leads to film property deterioration and film growth rate increase. Increasing process pressure at lower temperature can not only help to retrieve the film properties but further increase the film growth rate. These improvements can be attributed to the change of surface saturation level, the enhancement of precursor diffusion condition, as well as the higher probability for surface reactions to occur at the active sites. It suggests that increasing process pressure may reduce the necessary cycle times to obtain qualified film properties, which brings advantages of throughput for ALD semiconductor applications.

Atomic-scale oxygen-vacancy engineering in Sub-2 nm thin Al2O3/MgO memristors

“…This IL can arise from exposing the electrode to atmosphere during the fabrication process and from nonideal conditions during the deposition process in physical vapor depositions and chemical vapor depositions including atomic layer deposition (ALD) [15][16][17][18][19][20][21]. Among others, ALD has been utilized for the synthesis of metal-oxide based memristors, taking advantage of ALD's conformal coating over a large area and self-limiting deposition for atomic-scale thickness control [22][23][24][25]. For many metals, native metal oxides will form on the electrode surface if it has been exposed to ambient conditions prior to the ALD deposition of the M1/M2 active layer.…”

Multi-scale modelling and experimental analysis of ALD alumina

“…If these conditions are not ensured, non-uniform films are deposited. The process parameters (Li et al, 2007), the reactor design and the wafer position can thus affect the uniformity of the deposited films (Henn-Lecordier, et al, 2011, Salami et al, 2017.…”