Method for forming an oxynitride film in a semiconductor device

Abstract

A method for forming an oxide film in a semiconductor device comprises a pre-oxidation process, a main oxidation process and a post-oxidation process. N 2 O gas is used for the pre-oxidation process, a mixed gas of N 2 O gas and NH 3 gas is used for the main oxidation process, and N 2 O gas is used for the post-oxidation process. The insulation characteristics of the oxide film are increased by introducing nitrogen, and amount of introduced nitrogen can be regulated by the controlling of amount of NH 3 gas. Also, the problems encountered when NH 3 gas and N 2 O gas are used separately for the oxidation process can be solved by using of the mixed gas of NH 3 gas and N 2 O gas.

What is claimed is:  
     
       1. A method for forming an oxide film in a semiconductor device comprising: 
       a) initiating oxide film formation by introducing an nitrous oxide containing gas;  
       b) controlling the oxidation rate and influx of nitrogen by introducing ammonia into said nitrous oxide containing gas; and  
       c) halting the introducing of ammonia gas while maintaining the flow of nitrous oxide containing gas until formation of said oxide film is complete.  
     
     
       2. The method of  claim 1  further comprising the steps of: 
       
         prior to said initiating oxide film formation step, loading the semiconductor device into an oxidation chamber; and  
       
       
         introducing a nitrogen containing gas into said oxidation chamber. 
       
     
     
       3. The method of  claim 2  further comprising the step of increasing a temperature in said oxidation chamber from a first temperature to a second temperature during said introducing nitrogen containing gas step. 
     
     
       4. The method of  claim 3  wherein said first temperature is  700  degrees Celsius. 
     
     
       5. The method of  claim 3  wherein said second temperature is  900  degrees Celsius. 
     
     
       6. The method of  claim 1  further comprising the steps of: 
       
         supplying a nitrogen containing gas to an oxidation chamber containing said semiconductor device after said halting step; and  
       
       
         reducing a temperature in said oxidation chamber. 
       
     
     
       7. The method of  claim 1  wherein said initiating step is a pre- oxidation process.   
     
     
       8. The method of  claim 1  wherein said controlling step is a main oxidation process. 
     
     
       9. The method of  claim 1  wherein said halting step is a post- oxidation process.   
     
     
       10. The method of  claim 9  wherein said post- oxidation process prevents a possibility of nitridation in a substrate of said semiconductor device.   
     
     
       11. The method of  claim 9  wherein said post- oxidation process prevents a possibility of said ammonia penetrating said oxide film after said halting step.   
     
     
       12. The method of  claim 9  wherein said post- oxidation process prevents a possibility of degeneration of said oxide film by hydrogen ions in said ammonia.   
     
     
       13. The method of  claim 1  wherein during said controlling step, said ammonia and said nitrous oxide in said nitrous oxide containing gas are provided at a ratio which ranges between  0 . 5 %  and  20   % .   
     
     
       14. The method of  claim 1  wherein said controlling step produces an OH. 
     
     
       15. The method of  claim 14  wherein said OH accelerates said oxide film formation. 
     
     
       16. The method of  claim 1  wherein said controlling step is provided at a temperature of  900  degrees Celsius. 
     
     
       17. A method for forming an oxide film in a semiconductor device comprising the steps of: 
       
         introducing a nitrous oxide containing gas to the semiconductor device to initiate the film formation;  
       
       
         after introducing said nitrous oxide containing gas, mixing an ammonia containing compound with said nitrous oxide containing gas to control an oxidation rate and influx of nitrogen; and  
       
       
         halting the introduction of said ammonia containing compound while maintaining a flow of the nitrous oxide containing gas until formation of said oxide film is complete. 
       
     
     
       18. The method of  claim 17  further comprising the step of maintaining a flow rate of said nitrous oxide during said halting step until said film formation is complete. 
     
     
       19. The method of  claim 17  further comprising the steps of: 
       
         prior to said introducing step, loading a wafer into an oxidation chamber; and  
       
       
         introducing a nitrogen containing gas into said oxidation chamber. 
       
     
     
       20. The method of  claim 19  further comprising the step of: 
       
         raising a temperature in said oxidation chamber during said introducing nitrogen containing gas step from a first temperature to a second temperature. 
       
     
     
       21. The method of  claim 20  wherein said first temperature is  700  degrees Celsius. 
     
     
       22. The method of  claim 20  wherein said second temperature is  900  degrees Celsius. 
     
     
       23. The method of  claim 17  further comprising the steps of: 
       
         supplying a nitrogen containing gas after said halting step to an oxidation chamber containing the semiconductor device; and  
       
       
         dropping a temperature in said oxidation chamber. 
       
     
     
       24. The method of  claim 17  wherein said introducing a nitrous oxide containing gas is a pre- oxidation process.   
     
     
       25. The method of  claim 17  wherein said mixing step is a main oxidation process. 
     
     
       26. The method of  claim 17  wherein said halting step is a post- oxidation process.   
     
     
       27. The method of  claim 26  wherein said post- oxidation process prevents a possibility of nitridation in a substrate of said semiconductor device.   
     
     
       28. The method of  claim 26  wherein said post- oxidation process prevents a possibility of said ammonia in said ammonia containing compound penetrating said film after said halting step.   
     
     
       29. The method of  claim 17  wherein during said mixing step, said ammonia in said ammonia containing compound and said nitrous oxide in said nitrous oxide containing gas is at a ratio which ranges from  0 . 5 %  to  20   % .   
     
     
       30. The method of  claim 17  wherein said mixing step is performed at  900  degrees Celsius. 
     
     
       31. The method of  claim 17  wherein said OH accelerates said film formation. 
     
     
       32. A method for forming an oxide film on a semiconductor device comprising the steps of: 
       
         loading the semiconductor device into an oxidation chamber containing a nitrogen containing gas;  
       
       
         increasing a temperature of said oxidation chamber from a first temperature to a second temperature;  
       
         introducing a nitrous oxide containing gas into said oxidation chamber to initiate the film formation; said introducing step being a pre - oxidation process;    
       
         after introducing said nitrous oxide containing gas into said oxidation chamber, mixing an ammonia containing compound with said nitrous oxide containing gas to control an oxidation rate and influx of nitrogen, said mixing step being a main oxidation process;  
       
         halting the introduction of said ammonia containing compound while maintaining a flow of the nitrous oxide containing gas until formation of said oxide film is complete, said halting step being a post - oxidation process;    
       
         dropping a temperature in said oxidation chamber; and  
       
       
         supplying a nitrogen containing gas to said oxidation chamber. 
       
     
     
       33. The method of  claim 32  wherein during said halting step, a flow rate of said nitrous oxide containing gas is maintained after the halting of said ammonia until said film formation is completed. 
     
     
       34. The method of  claim 32  wherein said first temperature is  700  degrees Celsius. 
     
     
       35. The method of  claim 32  wherein said second temperature is  900  degrees Celsius. 
     
     
       36. The method of  claim 32  wherein said post- oxidation process prevents a possibility of said ammonia penetrating said film after said main oxidation process.   
     
     
       37. The method of  claim 32  wherein during said mixing step, said ammonia in said ammonia containing compound and said nitrous oxide in said nitrous oxide containing gas is at a ratio which ranges from  0 . 5 %  to  20   % .   
     
     
       38. The method of  claim 32  wherein during said mixing step produces an OH. 
     
     
       39. The method of  claim 38  wherein said OH accelerates said film formation. 
     
     
       40. The method of  claim 32  wherein said mixing step is performed at  900  degrees Celsius.