An ALD or CVD process for making a germanium-antimony-tellurium or germanium-bismuth-tellurium film on a surface of a substrate, the process comprising the steps of: introducing into a deposition chamber a germanium precursor selected from Ge(OR 14) 4-x L x, wherein L is selected from Cl, Br, I, or mixtures thereof; x is 0, 1, 2 or 3; R 14 is a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group; introducing into the deposition chamber a silyltellurium precursor selected from: (a) (b) (c) where R 1, R 2, R 3, R 4, R 5, and R 6 are independently selected from hydrogen, a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group; introducing into the deposition chamber a germanium precursor as defined above; introducing into the deposition chamber a silylantimony or silylbismuth precursor selected from: and tris(trimethylsilyl)bismuth, tris(triethylsilyl)bismuth or tris(tert-butyldimethylsilyl)bismuth; where R 1-10 are independently selected from hydrogen, a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group; R 11 and R 12 are independently selected from a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group, to form a silylantimony or silylbismuth monolayer; and repeating the steps above until a desired thickness is reached; wherein the term "alkyl" denotes a linear or branched functional group having from 1 to 10 carbon atoms and optionally including one or more functional groups selected from an alkoxy group and a dialkylamino group attached thereto. introducing into a deposition chamber a germanium precursor selected from Ge(OR 14) 4-x L x, wherein L is selected from Cl, Br, I, or mixtures thereof; x is 0, 1, 2 or 3; R 14 is a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group; introducing into the deposition chamber a silyltellurium precursor selected from: (a) (b) (c) where R 1, R 2, R 3, R 4, R 5, and R 6 are independently selected from hydrogen, a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group; (a) (b) (c) where R 1, R 2, R 3, R 4, R 5, and R 6 are independently selected from hydrogen, a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group; introducing into the deposition chamber a germanium precursor as defined above; introducing into the deposition chamber a silylantimony or silylbismuth precursor selected from: and tris(trimethylsilyl)bismuth, tris(triethylsilyl)bismuth or tris(tert-butyldimethylsilyl)bismuth; where R 1-10 are independently selected from hydrogen, a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group; R 11 and R 12 are independently selected from a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, a C 3 -C 10 cyclic alkyl group, a C 3 -C 10 cyclic alkenyl group, or a C 4 -C 10 aromatic group, to form a silylantimony or silylbismuth monolayer; and and tris(trimethylsilyl)bismuth, tris(triethylsilyl)bismuth or tris(tert-butyldimethylsilyl)bismuth; repeating the steps above until a desired thickness is reached; wherein the term "alkyl" denotes a linear or branched functional group having from 1 to 10 carbon atoms and optionally including one or more functional groups selected from an alkoxy group and a dialkylamino group attached thereto.