USRE44236EExpiredUtilityPatentIndex 59
Method for manufacturing semiconductor device

Assignee: YAMAUCHI SHOICHIPriority: Mar 31, 2004Filed: Oct 12, 2011Granted: May 21, 2013
Est. expiryMar 31, 2024(expired)· nominal 20-yr term from priority
Inventors:YAMAUCHI SHOICHI YAMAGUCHI HITOSHI MAKINO TOMOATSU NOGAMI SYOUJI YAMAOKA TOMONORI
D06M 13/00D06M 17/00D06M 11/00D06M 2200/30D06M 15/21H10D 62/051H10D 62/111H10D 84/038H10D 84/016H10D 30/665H10D 30/668
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Claims
Abstract

A method for manufacturing a semiconductor device includes the steps of: forming a trench in a semiconductor substrate; and forming an epitaxial film on the substrate including a sidewall and a bottom of the trench so that the epitaxial film is filled in the trench. The step of forming the epitaxial film includes a final step before the trench is filled with the epitaxial film. The final step has a forming condition of the epitaxial film in such a manner that the epitaxial film to be formed on the sidewall of the trench has a growth rate at an opening of the trench smaller than a growth rate at a position of the trench, which is deeper than the opening of the trench.
Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A method for manufacturing a semiconductor device comprising the steps of:
 forming a trench in a semiconductor substrate; and 
 forming an epitaxial film on the substrate including a sidewall and a bottom of the trench so that the epitaxial film is filled in the trench, wherein 
 the step of forming the epitaxial film includes a final step before the trench is filled with the epitaxial film, 
 the final step has a forming condition of the epitaxial film in such a manner that a mixture of a silicon source gas and a halogenide gas is used for forming the epitaxial film, 
 the step of forming the epitaxial film further includes a first step, 
 the first step is such that the epitaxial film having an impurity doped in the epitaxial film is formed on the bottom and the sidewall of the trench to have a predetermined thickness, 
 the final step is such that the epitaxial film having no impurity doped or a low concentration impurity doped in the epitaxial film is formed to fill an inside of the trench, and 
 the low concentration impurity of the epitaxial film in the final step has an impurity concentration lower than that in the first step. 
 
     
     
       2. The method according to  claim 1 , further comprising the step of:
 annealing the substrate after the step of forming the epitaxial film. 
 
     
     
       3. The method according to  claim 2 , wherein the first and the final steps in the step of forming the epitaxial film and the step of annealing the substrate are successively performed in epitaxial film forming equipment. 
     
     
       4. The method according to  claim 1 , wherein the first step is performed under a predetermined vacuum pressure lower than that of the final step. 
     
     
       5. The method according to  claim 4 , wherein the predetermined vacuum pressure of the first step is in a range between 1000 Pa and 1×10 −3  Pa. 
     
     
       6. A method for manufacturing a semiconductor device comprising the steps of:
 forming a trench in a semiconductor substrate; and 
 forming an epitaxial film on the substrate including a sidewall and a bottom of the trench so that the epitaxial film is filled in the trench, wherein 
 the step of forming the epitaxial film includes a final step before the trench is filled with the epitaxial film, 
 the final step has a forming condition of the epitaxial film in such a manner that a mixture of a silicon source gas and a halogenide gas is used for forming the epitaxial film, 
 the step of forming the epitaxial film further includes a first step and a vapor phase diffusion step, 
 the first step is such that the epitaxial film having an impurity doped in the epitaxial film is formed on the bottom and the sidewall of the trench to have a predetermined thickness, 
 the vapor phase diffusion step is such that an impurity is doped from a surface of the epitaxial film by a vapor phase diffusion method to form an impurity doped region in the epitaxial film, 
 the final step is such that the epitaxial film having no impurity doped or a low concentration impurity doped in the epitaxial film is formed to fill an inside of the trench, and 
 the low concentration impurity of the epitaxial film in the final step has an impurity concentration lower than that in the first step. 
 
     
     
       7. The method according to  claim 6 , wherein the vapor phase diffusion method is performed in such a manner that a dopant gas is supplied to the substrate, which is heated up to a predetermined temperature. 
     
     
       8. The method according to  claim 6 , further comprising the step of:
 annealing the substrate after the step of forming the epitaxial film. 
 
     
     
       9. The method according to  claim 8 , wherein the first, the vapor phase diffusion and the final steps in the step of forming the epitaxial film and the step of annealing the substrate are successively performed in epitaxial film forming equipment. 
     
     
       10. A method for manufacturing a semiconductor device comprising the steps of:
 forming a trench in a semiconductor substrate; and 
 forming an epitaxial film on the substrate including a sidewall and a bottom of the trench so that the epitaxial film is filled in the trench, wherein 
 the step of forming the epitaxial film includes a final step before the trench is filled with the epitaxial film, 
 the final step has a forming condition of the epitaxial film in such a manner that a mixture of a silicon source gas and a halogenide gas is used for forming the epitaxial film, 
 the step of forming the epitaxial film further includes a vapor phase diffusion step, 
 the vapor phase diffusion step is such that an impurity is doped from the bottom and the sidewall of the trench by a vapor phase diffusion method to form an impurity doped region in the bottom and the sidewall of the trench, 
 the final step is such that the epitaxial film having no impurity doped or a low concentration impurity doped in the epitaxial film is formed to fill an inside of the trench, and 
 the low concentration impurity of the epitaxial film in the final step has an impurity concentration lower than that in the impurity doped region of the bottom and the sidewall of the trench. 
 
     
     
       11. The method according to  claim 10 , wherein the vapor phase diffusion method is performed in such a manner that a dopant gas is supplied to the substrate, which is heated up to a predetermined temperature. 
     
     
       12. The method according to  claim 11 , further comprising the step of:
 annealing the substrate after the step of forming the epitaxial film. 
 
     
     
       13. The method according to  claim 12 , wherein the vapor phase diffusion and the final steps in the step of forming the epitaxial film and the step of annealing the substrate are successively performed in epitaxial film forming equipment. 
     
     
       14. A method for manufacturing a semiconductor device comprising the steps of:
 forming a trench in a semiconductor substrate; and 
 forming an epitaxial film on the substrate including a sidewall and a bottom of the trench so that the epitaxial film is filled in the trench, wherein 
 the step of forming the epitaxial film includes a final step before the trench is filled with the epitaxial film, 
 the final step has a forming condition of the epitaxial film in such a manner that a mixture of a silicon source gas and a halogenide gas is used for forming the epitaxial film, 
 the step of forming the epitaxial film further includes a first step, 
 the first step is such that the epitaxial film having no impurity doped or an impurity doped in the epitaxial film is formed on the bottom and the sidewall of the trench to have a predetermined thickness, 
 the final step is such that the epitaxial film having a high concentration impurity doped in the epitaxial film is formed to fill an inside of the trench, 
 the high concentration impurity of the epitaxial film in the final step has an impurity concentration higher than that in the first step, and 
 the final step is performed under a predetermine vacuum pressure lower than that of the first step. 
 
     
     
       15. The method according to  claim 14 , wherein the epitaxial film formed in the first step is a non-dope epitaxial film. 
     
     
       16. The method according to  claim 14 , wherein the predetermined vacuum pressure of the final step is in a range between 1000 Pa and 1×10 −3  Pa. 
     
     
       17. The method according to  claim 14 , further comprising the step of:
 annealing the substrate after the step of forming the epitaxial film. 
 
     
     
       18. The method according to  claim 17 , wherein the first and the final steps in the step of forming the epitaxial film and the step of annealing the substrate are successively performed in epitaxial film forming equipment. 
     
     
       19. A method for manufacturing a semiconductor device comprising:
 forming a trench in a semiconductor substrate; and   forming an epitaxial film on the substrate including a sidewall and a bottom of the trench so that the epitaxial film is filled in the trench,   wherein the forming of the epitaxial film has a forming condition of the epitaxial film in such a manner that the epitaxial film to be formed on the sidewall of the trench has a growth rate at an opening of the trench smaller than a growth rate at a position of the trench, which is deeper than the opening of the trench,   wherein the forming condition of the epitaxial film further includes that a growing surface of the epitaxial film on the sidewall of the trench has a taper angle with respect to a surface of the semiconductor substrate, the taper angle of the growing surface being smaller than a taper angle of the sidewall of the trench, and   wherein the forming condition of the epitaxial film further includes that a mixture of a silicon source gas and a halogenide gas is used for forming the epitaxial film.   
     
     
       20. The method according to claim 19,
 wherein the forming of the epitaxial film includes a final step before the trench is filled with the epitaxial film, and   wherein at least the final step has the forming condition.   
     
     
       21. The method according to claim 19,
 wherein the sidewall of the trench is perpendicular to the surface of the semiconductor substrate.   
     
     
       22. The method according to claim 19,
 wherein the forming condition has a growth rate of the epitaxial film to be formed on the bottom of the trench, the growth rate, being defined as R micrometer per minute,   wherein the forming condition further has a growth temperature, which is defined as T Kelvin,   wherein a relationship between the growth rate of R and the growth temperature of T is defined as an equation of:
   1000/T&gt;[log(R)+2.75]/2.72, 
   wherein the growth temperature of T is equal to or higher than (273+620) Kelvin, and equal to or lower than (273+1250) Kelvin.   
     
     
       23. The method according to claim 22,
 wherein the growth temperature of T is equal to or higher than (273+850) Kelvin, and equal to or lower than (273+1100) Kelvin.   
     
     
       24. The method according to claim 19,
 wherein the forming of the epitaxial film has a second forming condition of the epitaxial film in such a manner that the epitaxial film is formed under a chemical reaction control condition,   wherein the halogenide gas includes at least one of hydrogen chloride gas, chlorine gas, fluorine gas, chlorine triflouride gas, hydrogen fluoride gas and hydrogen bromide gas,   wherein the silicon source gas is monosilane gas or disilane gas, and   wherein the epitaxial film is formed at a temperature equal to or lower than (273+950) Kelvin.   
     
     
       25. The method according to claim 24,
 wherein the epitaxial film is formed at a temperature equal to or higher than (273+800) Kelvin under a pressure in a range between atmospheric pressure and 100 Pa, and   wherein the epitaxial film is formed at a temperature equal to or higher than (273+600) Kelvin under a pressure in a range between 100 Pa and 1×10 −5  Pa.   
     
     
       26. The method according to claim 25,
 wherein the semiconductor substrate is a silicon substrate,   wherein the bottom of the trench has a (110)-surface orientation of silicon crystal, and the sidewall of the trench has a (111)-surface orientation of the silicon crystal, or the bottom of the trench has a (100)-surface orientation of silicon crystal, and the sidewall of the trench has a (100)-surface orientation of the silicon crystal.   
     
     
       27. The method according to claim 19,
 wherein the forming of the epitaxial film has a second forming condition of the epitaxial film in such a manner that the epitaxial film is formed under a chemical reaction control condition,   wherein the halogenide gas includes at least one of hydrogen chloride gas, chlorine gas, fluorine gas, chlorine triflouride gas, hydrogen fluoride gas and hydrogen bromide gas,   wherein the silicon source gas is dichlorosilane gas, and   wherein the epitaxial film is formed at a temperature equal to or lower than (273+1100) Kelvin.   
     
     
       28. The method according to claim 27,
 wherein the epitaxial film is formed at a temperature equal to or higher than (273+800) Kelvin under a pressure in a range between atmospheric pressure and 100 Pa, and   wherein the epitaxial film is formed at a temperature equal to or higher than (273+600) Kelvin under a pressure in a range between 100 Pa and 1×10 −5  Pa.   
     
     
       29. The method according to claim 28,
 wherein the semiconductor substrate is a silicon substrate, and   wherein the bottom of the trench has a (110)-surface orientation of silicon crystal, and the sidewall of the trench has a (111)-surface orientation of the silicon crystal, or the bottom of the trench has a (100)-surface orientation of silicon crystal, and the sidewall of the trench has a (100)-surface orientation of the silicon crystal.   
     
     
       30. The method according to claim 19,
 wherein the forming of the epitaxial film has a second forming condition of the epitaxial film in such a manner that the epitaxial film is formed under a chemical reaction control condition,   wherein the halogenide gas includes at least one of hydrogen chloride gas, chlorine gas, fluorine gas, chlorine triflouride gas, hydrogen fluoride gas and hydrogen bromide gas,   wherein the silicon source gas is trichlorosilane gas, and   wherein the epitaxial film is formed at a temperature equal to or lower than (273+1150) Kelvin.   
     
     
       31. The method according to claim 30,
 wherein the epitaxial film is formed at a temperature equal to or higher than (273+800) Kelvin under a pressure in a range between atmospheric pressure and 100 Pa, and   wherein the epitaxial film is formed at a temperature equal to or higher than (273+600) Kelvin under a pressure in a range between 100 Pa and 1×10 −5  Pa.   
     
     
       32. The method according to claim 31,
 wherein the semiconductor substrate is a silicon substrate, and   wherein the bottom of the trench has a (110)-surface orientation of silicon crystal, and the sidewall of the trench has a (111)-surface orientation of the silicon crystal, or the bottom of the trench has a (100)-surface orientation of silicon crystal, and the sidewall of the trench has a (100)-surface orientation of the silicon crystal.   
     
     
       33. The method according to claim 19,
 wherein the forming of the epitaxial film has a second forming condition of the epitaxial film in such a manner that the epitaxial film is formed under a chemical reaction control condition,   wherein the halogenide gas includes at least one of hydrogen chloride gas, chlorine gas, fluorine gas, chlorine triflouride gas, hydrogen fluoride gas and hydrogen bromide gas,   wherein the silicon source gas is silicon tetrachloride gas, and   wherein the epitaxial film is formed at a temperature equal to or lower than (273+1200) Kelvin.   
     
     
       34. The method according to claim 33,
 wherein the epitaxial film is formed at a temperature equal to or higher than (273+800) Kelvin under a pressure in a range between atmospheric pressure and 100 Pa, and   wherein the epitaxial film is formed at a temperature equal to or higher than (273+600) Kelvin under a pressure in a range between 100 Pa and 1×10 −5  Pa.   
     
     
       35. The method according to claim 34,
 wherein the semiconductor substrate is a silicon substrate, and   wherein the bottom of the trench has a (110)-surface orientation of silicon crystal, and the sidewall of the trench has a (111)-surface orientation of the silicon crystal, or the bottom of the trench has a (100)-surface orientation of silicon crystal, and the sidewall of the trench has a (100)-surface orientation of the silicon crystal.   
     
     
       36. The method according to claim 19,
 wherein the halogenide gas functions as an etching gas in the forming of the epitaxial film in such a manner that an etching rate is determined by supply, and   wherein the silicon source gas provides the epitaxial film under a control of a chemical reaction condition.   
     
     
       37. A method for manufacturing a semiconductor device comprising:
 forming a trench in a semiconductor substrate; and   forming an epitaxial film on the substrate including a sidewall and a bottom of the trench so that the epitaxial film is filled in the trench,   wherein the forming of the epitaxial film has a forming condition of the epitaxial film in such a manner that the epitaxial film to be formed on the sidewall of the trench has a growth rate at an opening of the trench smaller than a growth rate at a bottom of the trench, and the growth rate of the epitaxial film on the sidewall of the trench is gradually increased with distance from the opening of the trench, and   wherein the forming condition of the epitaxial film further includes that a mixture of a silicon source gas and a halogenide gas is used for forming the epitaxial film.
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