In this work, we succeeded in the preparation of LiNb 1- x Ta x O 3 films on Si(111) substrates by means of sol gel process, and the usual sol gel process for the preparation of LiNbO 3 and LiTaO 3 films on Si substrates was improved by adding a 33% aqueous solution of CH 3CH 2OH to the mixed sols of LiNb(OCH 2CH 3) 6 and LiTa(OCH 2CH 3) 6 . The crystallization behavior of LiNb 1- x Ta x O 3 films on Si(111) substrates has been studied. Highly c axis oriented LiNb 1- x Ta x O 3 films have been obtained within the tantalum composition range of {0< x <0 33}. Some factors such as the hydrogen termination of the silicon surface, the RTP annealing process that provides the unidirectional heat flow and the preheating temperature are discussed to analyze the crystallization of the c axis oriented films. In this work, we succeeded in the preparation of LiNb 1- x Ta x O 3 films on Si (111) substrates by means of sol gel process, and the usual sol gel process for the preparation of LiNbO 3 and LiTaO 3 films on Si The substrates were improved by adding a 33% aqueous solution of CH 3 CH 2OH to the mixed sols of LiNb (OCH 2 CH 3) 6 and LiTa (OCH 2 CH 3) 6. The crystallization behavior of LiNb 1-x Ta x O 3 films on Si (111) substrates have been studied. Highly c-axis oriented LiNb 1-x Ta x O 3 films have been obtained within the tantalum composition range of {0