Low temperature etchant for treatment of silicon-containing surfaces

Abstract

Embodiments provide a method for etching or smoothing a silicon material on a substrate. In one example, the method provides positioning a substrate containing a contaminant disposed on a silicon material within a process chamber, heating the substrate to a temperature of less than 800° C., and exposing the silicon material to an etching gas that contains a chlorine-containing gas and a silicon source gas. The contaminant and a predetermined thickness of the silicon material are removed during the etching process. In another example, the method provides that the substrate contains a first silicon surface having a surface roughness of about 1 nm RMS or greater, exposing the substrate to the etching gas to form a second silicon surface from the first silicon surface during a smoothing process, wherein the second silicon surface has a surface roughness of less than 1 nm RMS.

1 . A method for etching a silicon material on a substrate surface, comprising: 
 positioning a substrate comprising a silicon-containing material within a process chamber, wherein a contaminant is disposed on the silicon-containing material;    heating the substrate to a temperature of less than 800° C.; and    exposing the silicon-containing material to an etching gas comprising a chlorine-containing gas and a silicon source gas to remove the contaminant and a predetermined thickness of the silicon-containing material during an etching process.    
   
   
       2 . The method of  claim 1 , wherein the chlorine-containing gas comprises a source gas selected from the group consisting of chlorine gas, chlorine trifluoride, tetrachlorosilane, derivatives thereof, and combinations thereof.  
   
   
       3 . The method of  claim 1 , wherein the silicon-containing material is removed at a rate within a range from about 2 Å per minute to about 20 Å per minute.  
   
   
       4 . The method of  claim 3 , wherein the temperature of the substrate is within a range from about 500° C. to about 700° C.  
   
   
       5 . The method of  claim 1 , wherein the etching gas comprises a carrier gas selected from the group consisting of nitrogen, argon, helium, and combinations thereof.  
   
   
       6 . The method of  claim 5 , wherein the silicon source gas is selected from the group consisting of silane, disilane, methylsilane, derivatives thereof, and combinations thereof.  
   
   
       7 . The method of  claim 6 , wherein the carrier gas comprises nitrogen and the silicon source gas comprises silane.  
   
   
       8 . The method of  claim 1 , wherein an epitaxy deposition process is conducted within the process chamber subsequent the etching process.  
   
   
       9 . The method of  claim 1 , wherein the contaminant comprises a species selected from the group consisting of oxide, fluoride, chloride, nitride, organic residue, carbon, derivatives thereof, and combinations thereof.  
   
   
       10 . The method of  claim 9 , wherein the substrate is exposed to a wet clean process prior to positioning the substrate within the process chamber.  
   
   
       11 . The method of  claim 10 , wherein the substrate is exposed to ambient conditions for a time period within a range from about 6 hours to about 24 hours subsequent the wet clean process and prior to positioning the substrate within the process chamber.  
   
   
       12 . The method of  claim 9 , wherein the silicon-containing material further comprises a rough surface that is removed during the etching process.  
   
   
       13 . A method for smoothing a silicon-containing material on a substrate surface, comprising: 
 positioning a substrate comprising a first silicon-containing surface within a process chamber, wherein the first silicon-containing surface comprises a surface roughness of about 1 nm RMS or greater;    heating the substrate to a temperature of less than 800° C.; and    exposing the substrate to an etching gas comprising a chlorine-containing gas and a silicon source gas to form a second silicon-containing surface from the first silicon-containing surface during a smoothing process, wherein the second silicon-containing surface comprises a surface roughness of less than 1 nm RMS.    
   
   
       14 . The method of  claim 13 , wherein the chlorine-containing gas comprises a source gas selected from the group consisting of chlorine gas, chlorine trifluoride, tetrachlorosilane, derivatives thereof, and combinations thereof.  
   
   
       15 . The method of  claim 13 , wherein a predetermined thickness of the first silicon-containing surface is removed at a rate within a range from about 2 Å per minute to about 20 Å per minute.  
   
   
       16 . The method of  claim 15 , wherein the temperature of the substrate is within a range from about 500° C. to about 700° C.  
   
   
       17 . The method of  claim 13 , wherein the etching gas comprises a carrier gas selected from the group consisting of nitrogen, argon, helium, and combinations thereof.  
   
   
       18 . The method of  claim 17 , wherein the silicon source gas is selected from the group consisting of silane, disilane, methylsilane, derivatives thereof, and combinations thereof.  
   
   
       19 . A method for forming a silicon-containing monocrystalline material on a substrate, comprising: 
 exposing a substrate to a HF-last wet clean solution during a preclean process;    positioning the substrate within a process chamber, wherein the substrate comprises a silicon-containing monocrystalline surface;    heating the substrate to a temperature of less than 800° C.;    exposing the substrate to an etching gas comprising a chlorine-containing gas and a silicon source gas to remove a predetermined thickness of the silicon-containing monocrystalline surface while forming an exposed monocrystalline surface; and    depositing an epitaxy layer on the exposed monocrystalline surface within the process chamber.    
   
   
       20 . The method of  claim 19 , wherein the chlorine-containing gas comprises a source gas selected from the group consisting of chlorine gas, chlorine trifluoride, tetrachlorosilane, derivatives thereof, and combinations thereof.  
   
   
       21 . The method of  claim 20 , wherein the silicon source gas is selected from the group consisting of silane, disilane, methylsilane, derivatives thereof, and combinations thereof.  
   
   
       22 . The method of  claim 21 , wherein the etching gas comprises a carrier gas selected from the group consisting of nitrogen, argon, helium, and combinations thereof.  
   
   
       23 . The method of  claim 19 , wherein the epitaxy layer is deposited by a deposition gas containing chlorine gas.  
   
   
       24 . The method of  claim 19 , further comprising cleaning the process chamber with the etching gas to remove a silicon-containing contaminant adhered on an inner surface of the process chamber during a post-clean process subsequent to the deposition of the epitaxy layer.  
   
   
       25 . The method of  claim 24 , wherein the process chamber is heated to a temperature within a range from about 500° C. to about 700° C. during the post-clean process.  
   
   
       26 . The method of  claim 24 , wherein nitrogen is co-flowed with chlorine gas during the post-clean process.