Film-forming manufacturing apparatus and method

Abstract

It is an object of the present invention to provide a film-forming apparatus and a film-forming method that can prolong the lifetime of heaters used under high temperature conditions in an epitaxial growth technique. An inert gas discharge portion supplies an inert gas into the space containing the heater, gas is then discharged through the gas discharge portion without influence on the semiconductor substrate during film formation. It is therefore possible to prevent the reaction gas entering into the space containing the high-temperature heaters. This makes it possible to prevent a reaction between hydrogen gas contained in the reaction gas and SiC constituting the heaters. Therefore, it is possible to prevent carbon used as a base material of the heaters from being exposed due to the decomposition of SiC and then reacting with hydrogen gas. This makes it possible to prolong the lifetime of the heaters.

What is claimed is: 
     
         1 . A film-forming apparatus comprising:
 a film-forming chamber;   a reaction gas supply portion;   a susceptor provided in the film-forming chamber to place a substrate thereon;   an upper heater located above the susceptor; and   a lower heater located below the susceptor;   an upper liner, functioning as a channel through which the reaction gas flows downward from the reaction gas supply portion toward the susceptor;   a lower liner provided with an opening for placing the substrate on to the susceptor;   a lifting system positioned outside the film-forming chamber, for controlling lifting and lowering of the lower liner section.   
     
     
         2 . The film-forming apparatus according to  claim 1 , wherein the lower liner is two separate liners, wherein one liner has the opening for placing the substrate on to the susceptor. 
     
     
         3 . The film-forming apparatus according to  claim 1 , wherein the liners are cylindrically-shaped. 
     
     
         4 . The film-forming apparatus according to  claim 1 , wherein the reaction gas supply portion is located in the upper part of the film-forming chamber. 
     
     
         5 . A film-forming apparatus comprising:
 a film-forming chamber;   a hollow liner provided in the film-forming chamber;   a susceptor provided in the film-forming chamber to place a substrate thereon;   a heater located below the susceptor;   a reaction gas supply portion for supplying a reaction gas;   a first inert gas supply portion that supplies a first inert gas into a space around the susceptor;   a second inert gas supply portion that supplies a second inert gas into a space around the heater;   a inert gas discharge portion for discharging the second inert gas from a space around the heater; and   a gas discharge portion, through which reaction gas, the first inert gas and the second inert gas are discharged outside the film-forming chamber.   
     
     
         6 . The film-forming apparatus according to  claim 5 , wherein the hollow liner is cylindrically-shaped. 
     
     
         7 . The film-forming apparatus according to  claim 5 , wherein the reaction gas supply portion is located in the upper part of the film-forming chamber. 
     
     
         8 . The film-forming apparatus according to  claim 5 , wherein the film-forming chamber includes two heaters:
 an upper heater located in a space between the liner and the inner wall of the film-forming chamber; and   a lower heater located below the susceptor.   
     
     
         9 . The film-forming apparatus according to  claim 8 , further comprising a reflector provided above the upper heater. 
     
     
         10 . The film-forming apparatus according to  claim 5 , wherein the inert gas is argon gas. 
     
     
         11 . A film-forming method comprising:
 placing a substrate on a susceptor within a film-forming chamber;   and supplying a reaction gas into the film-forming chamber while the substrate is heated by an upper heater provided above the substrate, and a lower heater provided below the substrate to form a predetermined film on the substrate;   the lower heater is kept under an inert gas atmosphere via supplied inert gas,   wherein a pressure in a first space around the susceptor is kept at a lower pressure than a pressure in a second space around the upper heater and a pressure in a third space around the lower heater;   the inert gas used to create the inert gas atmosphere and the reaction gas used to form a predetermined film are then discharged from a fourth space of the film-forming chamber.   
     
     
         12 . The film-forming method according to  claim 11 , wherein a pressure in a fourth space, from which the reaction gas and the inert gas are discharged, is lower than all the pressure in the first space, the pressure in the second space, and the pressure in the third space.