Low Temperature Plasma-Enhanced Atomic Layer Deposition of Metal Oxide Thin Films

Many reported ALD processes are carried out at elevated temperatures (> 100 ºC), which is problematic for temperature-sensitive substrates. Plasma-enhanced ALD routes may provide a solution, as the ALD temperature window can be extended to lower deposition temperatures. As such, the plasma-enhanced ALD of aluminium oxide, titanium dioxide and tantalum oxide has been investigated at 25-150 ºC using trimethylaluminium, titanium isopropoxide, methylcyclopentadienyltris(isopropoxy)titanium and pentakis(dimethylamido)tantalum respectively as precursors. An oxygen plasma was employed as the oxygen source. We have demonstrated metal oxide thin film deposition at temperatures as low as room temperature and compared the results with corresponding thermal ALD routes to the same materials.