Oxhalide precursors
The invention provides a process for preparing molybdenum and tungsten oxyhalide compounds which are useful in the deposition of molybdenum and tungsten containing films on various surfaces of microelectronic devices. In the process of the invention, a molybdenum or tungsten trioxide is heated in either a solid state medium or in a melt-phase reaction comprising a eutectic blend comprising alkaline and/or alkaline earth metal salts. The molybdenum or tungsten oxyhalides thus formed may be isolated as a vapor and crystallized to provide highly pure precursor compounds such as MoO 2 Cl 2 .
1 . A process for preparing compounds of the formula MO y X z , wherein M is chosen from molybdenum and tungsten, and X is chosen from chloro, fluoro, bromo, and iodo, y is 1 or 2, and z is 2 or 4, which comprises contacting a compound of the formula
with at least one compound of the formula A-X, wherein A is chosen from elements of Group 1, Group 2, transitions metals, and main-group elements, at a temperature of about 200° to about 900° C., wherein the contacting produces multiple compounds of the formula MO y X z and the contacting is conducted under a regime of fractional sublimation to separate MO 2 Z 2 and MOZ 4 into pure products.
2 . The process of claim 1 , wherein A is chosen from lithium, sodium, and potassium.
3 . The process of claim 1 , wherein X is chloro.
4 . The process of claim 1 , wherein A is chosen from magnesium, calcium, strontium, barium, beryllium, scandium, titanium, vanadium, and chromium.
5 . The process of claim 1 , wherein the at least one compound of the formula A-X are comprised of a mixture of lithium chloride and potassium chloride.
6 . The process of claim 1 , further comprising collecting a compound of the formula MO y X z as a vapor and allowing said vapor to cool, thereby forming a crystalline form of the compound of the formula MO y X z .
7 . The process of claim 1 , wherein a compound of the formula MO y X z is MoO 2 Cl 2 .
8 . The process of claim 1 , wherein a compound of the formula MO y X z is MoOCl 4 .
9 . The process of claim 1 , wherein a compound of the formula MO y X z is WO 2 Cl 2 .
10 . The process of claim 1 , wherein a compound of the formula MO y X z is WOCl 4 .
11 . The process of claim 1 , wherein the compounds of the formula MO y X z are produced using just heat energy.
12 . The process of claim 1 , further comprising flowing a carrier gas to assist transport of the compounds of the formula MO y X z .
13 . The process of claim 1 , wherein a ratio of MO 3 to A-X is controlled to adjust a ratio between MO 2 Z 2 and MOZ 4 produced.