Low temperature MOCVD growth of V/VI materials via a Me3SiNMe2 elimination reaction

Abstract

The reactive precursors M(NMe/sub 2/)/sub 3/ (M=Sb, Bi) and (Me/sub 1/Si)/sub 2/Te were used to deposit films of M/sub 2/Te/sub 3/ (M=Sb, Bi) on Si(111) cut 4/spl deg/ off-axis, GaAs(100), and Kapton substrates between 25/spl deg/C and 150/spl deg/C in a low pressure MOCVD reactor. The film growth process is a novel N,N-dimethylamino-trimethylsilane (Me/sub 3/SiNMe/sub 2/) elimination reaction and not pyrolysis reactions employed in conventional MOCVD techniques. X-ray diffraction data show the crystalline quality and orientation of the resulting polycrystalline films were dependent on the substrate structure and growth temperature. Amorphous films were deposited below 50/spl deg/C. Films deposited at 75/spl deg/C for Sb/sub 2/Te/sub 3/ and 125/spl deg/C for Bi/sub 2/Te/sub 3/ were highly oriented with the (015) reflection plane parallel to the substrate surface. Films of Sb/sub 2/Te/sub 3/ deposited at 150/spl deg/C were highly oriented with the [00l] reflection planes parallel to the substrate surface. The electrical properties and composition of Bi/sub 2/Te/sub 3/ films deposited at 125/spl deg/C on Kapton were independent of the V/VI precursor ratio used. Variation in the composition of a Sb/sub x/Bi/sub 2-x/Te/sub 3/ ternary film across the susceptor was observed due to differences in the reaction kinetics for formation of Sb/sub 2/Te/sub 3/ and Bi/sub 2/Te/sub 3/. This unique deposition reaction provides an alternative route to prepare group V chalcogenide materials which have potential applications in solar cells, reversible optical storage, and thermoelectrics.