GROWTH OF HIGHLY ORIENTED TIO2 THIN-FILMS ON INP(100) SUBSTRATES BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

We have studied the growth of highly oriented titanium dioxide (TiO2) thin films on InP(100) substrates at low-temperature by metalorganic c hemical vapor deposition (MOCVD), The TiO2 thin films were deposited a t a substrate temperature between 300 and 450 degrees C with a differe nt supply ratio of oxygen to the titanium organometallic source of tit anium isopropoxide. X-ray diffraction patterns showed the formation of the highly oriented rutile phase with the [110] direction perpendicul ar to the InP(100) substrate for films grown at a temperature above 35 0 degrees C, while the sample grown at 300 degrees C indicated a mixed structure with anatase (101) and (200) and rutile (211) and (220) pea ks. Scanning electron microscopy (SEM) for the films grown at temperat ures above 350 degrees C showed a highly oriented, dense columnar stru cture. It was suggested that the molar ratio of oxygen gas to the orga nometallic Ti source is an important parameter to obtain rutile phase TiO2 films at low growth temperature by low temperature MOCVD. From ca pacitance-voltage and current-voltage measurements of the Al/TiO2/n-In P structure, the dielectric constant was approximately about 90 with a good rectification behavior and low reverse leakage current.