Method and apparatus for the selective deposition of epitaxial germanium stressor alloys

Abstract

A method and apparatus for forming heterojunction stressor layers is described. A germanium precursor and a metal precursor are provided to a chamber, and an epitaxial layer of germanium-metal alloy formed on the substrate. The metal precursor is typically a metal halide, which may be provided by subliming a solid metal halide or by contacting a pure metal with a halogen gas. The precursors may be provided through a showerhead or through a side entry point, and an exhaust system coupled to the chamber may be separately heated to manage condensation of exhaust components.

What is claimed is: 
     
         1 . An apparatus for forming a stressor layer on a substrate, comprising:
 a rotatable substrate support disposed in an enclosure;   a plurality of gas inlets formed in a first wall of the enclosure;   at least one gas outlet formed in a second wall of the enclosure;   a reactive precursor source coupled to a gas inlet by a first conduit;   a non-reactive precursor source coupled to a gas inlet by a second conduit; and   an exhaust system comprising a condensation trap.   
     
     
         2 . The apparatus of  claim 1 , wherein at least one gas inlet of the plurality of gas inlets is formed in the first wall of the enclosure near the rotatable substrate support. 
     
     
         3 . The apparatus of  claim 1 , wherein the exhaust system further comprises jacketed piping and valves. 
     
     
         4 . The apparatus of  claim 3 , wherein the exhaust system further comprises a vacuum pump and the jacketed piping ends at an inlet of the vacuum pump. 
     
     
         5 . The apparatus of  claim 3 , wherein the exhaust system further comprises an adhesion reducing coating. 
     
     
         6 . The apparatus of  claim 1 , wherein the reactive precursor source is coupled to a metal halide source. 
     
     
         7 . The apparatus of  claim 1 , wherein the non-reactive precursor source is a germanium hydride source. 
     
     
         8 . The apparatus of  claim 1 , further comprising a metal precursor contact chamber coupled with the first conduit, wherein the contact chamber contains a bed of solid metal or metal halide crystals. 
     
     
         9 . The apparatus of  claim 8 , further comprising a halogen gas source coupled with the metal precursor contact chamber through a first gas feed conduit. 
     
     
         10 . The apparatus of  claim 9 , further comprising a carrier gas source coupled with the metal precursor contact chamber through a second gas feed conduit. 
     
     
         11 . An apparatus for forming a stressor layer on a substrate, comprising:
 a rotatable substrate support disposed in an enclosure;   a heat source disposed in the enclosure below the rotatable substrate support;   a gas inlet formed in a sidewall of the enclosure proximate to an edge of the substrate support and having a flow direction substantially parallel to an upper surface of the rotatable substrate support;   a gas outlet formed in a sidewall opposite the gas inlet and proximate to the edge of the rotatable substrate support;   a first precursor pathway coupled to the gas inlet and to a germanium hydride source;   a second precursor pathway coupled to the gas inlet and to a metal halide source or organometallic halide source; and   an exhaust system comprising an exhaust conduit and valves coupling the gas outlet to a vacuum pump, wherein the exhaust conduit is encompassed by a jacket.   
     
     
         12 . The apparatus of  claim 11 , wherein the jacket includes resistive heating elements. 
     
     
         13 . The apparatus of  claim 11 , further comprising a condensation trap coupled to the exhaust conduit. 
     
     
         14 . The apparatus of  claim 11 , wherein the exhaust conduit is coated with quartz or an inert polymer material. 
     
     
         15 . The apparatus of  claim 11 , further comprising a metal precursor contact chamber coupled with the second precursor pathway, wherein the contact chamber contains a bed of solid metal or metal halide crystals. 
     
     
         16 . The apparatus of  claim 15 , further comprising a halogen gas source coupled with the metal precursor contact chamber through a first gas feed conduit. 
     
     
         17 . The apparatus of  claim 16 , further comprising a carrier gas source coupled with the metal precursor contact chamber through a second gas feed conduit.