Fabrication of semiconductor device oxide at lower temperature using pre-dissociated chlorohydrocarbon

Abstract

The invention provides a method of fabricating a semiconductor device. In one aspect, the method comprises heating a gas mixture comprising chlorohydrocarbon having a general formula of C x H x Cl x , wherein x=2, 3, or 4, by passing it through a first chamber packed with surface area expanding members heated to a temperature to substantially dissociate the chlorohydrocarbon into chlorine and hydrocarbon. The dissociated chlorohydrocarbon is then passed, together with oxygen, into a second chamber heated to a lesser temperature to form an oxide film on a semiconductor substrate.

1 . A method of fabricating a semiconductor device, comprising:
 flowing a gas mixture comprising chlorohydrocarbon having a general formula of C x H x Cl x , wherein x=2, 3, or 4, from a supply source at a given flow rate through a first chamber packed with quartz beads and heated to a first temperature to substantially dissociate the chlorohydrocarbon as it passes through the first chamber; and   transmitting the gas mixture comprising the dissociated chlorohydrocarbon, together with oxygen, to a second chamber heated to a second temperature less than the first temperature to form an oxide film on a surface of a semiconductor substrate.   
   
   
       2 . The method of  claim 1 , wherein the first temperature is greater than 900° C. and the second temperature is less than 700° C. 
   
   
       3 . The method of  claim 2 , wherein the flow rate is 4 to 11 liters per minute. 
   
   
       4 . The method recited in  claim 3 , wherein the chlorohydrocarbon is trans-dichloroethylene, cis-dichloro-ethylene, 1,1-dichloroethylene, or mixtures thereof. 
   
   
       5 . The method recited in  claim 1 , wherein forming the oxide film comprises forming the oxide film to a thickness less than 8 nm. 
   
   
       6 . The method recited in  claim 1 , wherein about 90% to about 100% of the chlorohydrocarbon is dissociated in the first chamber. 
   
   
       7 . A method of fabricating a semiconductor device, comprising:
 flowing a gas mixture comprising chlorohydrocarbon having a general formula of C x H x Cl x , wherein x=2, 3, or 4, from a supply source at a given flow rate through a first chamber packed with quartz beads and heated to a first temperature greater than 900° C. to dissociate at least 90% of the chlorohydrocarbon as it passes through the first chamber; and   transmitting the gas mixture comprising the dissociated chlorohydrocarbon, together with oxygen, to a second chamber heated to a second temperature less than about 800° C. to form an oxide film on a surface of a semiconductor substrate.   
   
   
       8 . The method of  claim 7 , wherein the flow rate is 4 to 11 liters per minute. 
   
   
       9 . The method recited in  claim 8 , wherein the chlorohydrocarbon is trans-dichloroethylene, cis-dichloro-ethylene, 1,1-dichloroethylene, or mixtures thereof. 
   
   
       10 . The method recited in  claim 9 , wherein forming the oxide film comprises forming the oxide film to a thickness less than 8 nm. 
   
   
       11 . A method of fabricating a semiconductor device, comprising:
 flowing a gas mixture comprising chlorohydrocarbon having a general formula of C x H x Cl x , wherein x=2, 3, or 4, from a supply source at a given flow rate through a first chamber packed with surface area increasing members heated to a first temperature to substantially completely dissociate the chlorohydrocarbon into chlorine and hydrocarbon as it passes through the first chamber; and   transmitting the gas mixture comprising the dissociated chlorine and hydrocarbon, together with oxygen, to a second chamber heated to a second temperature less than the first temperature to form an oxide film on a surface of a semiconductor substrate.   
   
   
       12 . The method of  claim 11 , wherein the first temperature is greater than 900° C. and the second temperature is less than 700° C. 
   
   
       13 . The method of  claim 11 , wherein the surface area increasing members comprise glass. 
   
   
       14 . The method of  claim 13 , wherein the surface area increasing members are quartz beads. 
   
   
       15 . The method of  claim 11 , wherein the first chamber has internal walls, the surface area increasing members are members separate from the chamber walls, and the surface area increasing members increase the heated internal surface area encountered by the gas mixture passing through the first chamber by 10 to 140 times over the surface area of the chamber walls.. 
   
   
       16 . The method recited in  claim 11 , wherein forming the oxide film comprises forming the oxide film to a thickness less than about 8 nm.