Atomic Layer Deposition and Properties of Lanthanum Oxide and Lanthanum‐Aluminum Oxide Films

Atomic layer deposition (ALD) of lanthanum oxide on glass and silicon substrates was examined using lanthanum silylamide, La[N(SiMe 3 ) 2 ] 3 , and water as precursors in the substrate temperature range of 150–250 °C. The effect of pulse times and precursor evaporation temperature on the growth rate and refractive index was investigated. The films remained amorphous regardless of the deposition conditions. The resulting La 2 O 3 films contained noticeable amounts of hydrogen and silicon and were chemically unstable while stored in ambient air. Lanthanum aluminum oxide films were achieved with stoichiometry close to that of LaAlO 3 at 225 °C from La[N(SiMe 3 ) 2 ] 3 , Al(CH 3 ) 3 , and H 2 O. The lanthanum β‐diketonate precursor, La(thd) 3 , was used as the reference precursor.