Liquid injection MOCVD and ALD studies of “single source” Sr-Nb and Sr-Ta precursors

Abstract

A range of "single source" Sr-Nb and Sr-Ta heterometal alkoxides precursors are investigated as potential sources for liquid injection MOCVD (metalorganic chemical vapour deposition) and ALD (atomic layer deposition) of SrBi 2 Ta 2 O 9 (SBT) and SrBi 2 (T x Nb 1-x ) 2 O 9 (SBTN). These "single source" precursors are designed to alleviate the mis-match between conventional Sr and Ta or Sr and Nb sources. Strontium-tantalate and strontium-niobate thin films were deposited on silicon using the "single source" alkoxide precursors [Sr{Ta(OEt) 5 (dmae} 2 ] and [Sr{Nb(OEt) 5 (dmae)} 2 ] (dmae = OCH 2 CH 2 NMe 2 ), and the optimum temperatures for deposition of stoichiometric SrTa 2 O 6 and SrNb 2 O 6 were determined. Separate ALD studies of [Sr{Ta(OEt) 5 (dmae)} 2 ] and [Sr{Ta(OEt) 5 (mee)} 2 ] (mee = OCH 2 CH 2 OMe) for the growth of strontium-tantalate were carried out to assess precursor suitability for this technique. Liquid injection MOCVD of Bi-oxide films using Bi(mmp) 3 indicates similar decomposition behaviour to the Sr-Ta and Sr-Nb alkoxides, demonstrating its suitability as a complementary source of Bi for SBT, SBN and SBTN.