Low temperature GST process
A deposition process to form a conformal phase change material film on the surface of a substrate to produce a memory device wafer comprises providing a substrate to a chamber of a deposition system; providing an activation region; introducing one or more precursors into the chamber upstream of the substrate; optionally introducing one or more co-reactants upstream of the substrate; activating the one or more precursors; heating the substrate; and depositing the phase change material film on the substrate from the one or more precursors by chemical vapor deposition. The deposited phase change material film comprises Ge x Sb y Te z A m in which A is a dopant selected from the group of N, C, In, Sn, and Se. In one implementation, the process is carried out to form GST films doped with carbon and nitrogen, to impart beneficial film growth and performance properties to the film.
1. A process for forming a germanium telluride material on a substrate, comprising vaporizing germanium and tellurium precursors, to form corresponding precursor vapor; heating the tellurium precursor vapor to temperature sufficient for activation thereof, separate from the germanium precursor; contacting the germanium precursor vapor and activated tellurium precursor vapor with the substrate under conditions enabling formation of said germanium telluride material on the substrate, wherein the germanium telluride material comprises material of the formula Ge x Te z A m , wherein A comprises one or more elements selected from the group consisting of N, C, In, Sn, and Se, and wherein x is from 0.1 to 0.6, z is from 0.2 to 0.9, and m is from 0 to 0.15.
2. The process of claim 1 , wherein the substrate during said contacting is at temperature below the crystallization temperature of said germanium telluride material.
3. The process of claim 1 , wherein the substrate during said contacting is at temperature in a range of from 110° C. to 300° C.
4. The process of claim 1 , wherein the tellurium precursor vapor is heated in said heating to temperature in a range of from 180° C. to 450° C. for activation thereof.
5. The process of claim 1 , wherein the germanium precursor comprises a precursor selected from the group consisting of Ge(IV) amides, Ge(IV) mixed alkyl/amides, Ge(II) amidinates, Ge(II) amides, Ge(IV) guanidinates, germylenes, and Ge(II)Cp, wherein Cp is cyclopentadienyl.
6. The process of claim 1 , wherein the germanium precursor comprises Ge[Pr i NC(n-Bu)NPr i ] 2 .
7. A process for forming a germanium telluride material on a substrate, comprising vaporizing germanium and tellurium precursors, to form corresponding precursor vapor; heating the tellurium precursor vapor to temperature sufficient for activation thereof, separate from the germanium precursor;
contacting the germanium precursor vapor and activated tellurium precursor vapor with the substrate under conditions enabling formation of said germanium telluride material on the substrate, wherein the tellurium precursor comprises a precursor of the formula TeL n or cyclic LTe(-L-) 2 TeL, wherein at least one L contains a N bonded to one said Te, n is between 2-6, inclusive, and each L is independently selected from the alkyl and aryl groups consisting of: amides of the form —NR 1 R 2 wherein R 1 , R 2 represents H, an alkyl group, or a silyl group; cyclic amides of the form —NR wherein R represents a C 1 -C 6 linear, branched, cyclic, or silyl group; imido groups of the form ═NR wherein R represents a C 1 -C 6 linear, branched, cyclic, or silyl group; a group of the form —N(R)—, wherein the —N(R)— bridges 2 telluriums; diamides of the form —NR 1 -A-R 2 N— wherein R 1 , R 2 and A, are, independently, a C 1 -C 6 linear, branched, cyclic, or silyl group; aminoamide groups of the form —NR 1 -A-NR 2 R 3 wherein R 1 , R 2 , R 3 and A are, independently, a C 1 -C 6 linear, branched, cyclic, or silyl group; alkoxyamide groups of the form —NR 1 -A-OR 2 wherein R 1 , R 2 and A are, independently, a C 1 -C 6 linear, branched, cyclic, or silyl group; amidinate groups of the form —NR 1 —C(R 2 )—NR 3 wherein R 1 , R 2 , R 3 are, independently, a C 1 -C 6 linear, branched, cyclic, or silyl group; and guanidinate groups of the form —NR 1 —C(NR 2 R 3 )—NR 4 wherein R 1 , R 2 , R 3 , R 4 are, independently, a C 1 -C 6 linear, branched, cyclic, or silyl group.