Device for doping, deposition or oxidation of semiconductor material at low pressure

Abstract

A device for doping, deposition or oxidation of semiconductor material at low pressure in a process tube, is provided with a tube closure as well as devices for supplying and discharging process gases and for generating a negative pressure in the process tube. A closure of the process chamber that is gas tight with respect to the process gases and the vacuum tight seal of the end of the tube closure are spatially separated from each other in relation to the atmosphere and are arranged on a same side of the process tube in such a manner that a bottom of a stopper, sealing the process chamber, rests against a sealing rim of the process tube and the tube closure end is sealed vacuum tight by means of a collar, which is attached to the process tube and against which a door rests sealingly.

1 . Device for doping, deposition or oxidation of semiconductor material at low pressure in a process chamber of a process tube, wherein: the process tube is provided with a tube closure as well as with devices for supplying and discharging process gases and for generating a negative pressure in the process tube, a closure of the process chamber that is gas tight with respect to the process gases and a vacuum tight seal of the end of the tube closure are spatially separated from each other in relation to atmosphere and are arranged on a same side of the process tube in such a manner that a bottom of a stoppers, sealing the process chamber, rests against a sealing rim of the process tube and the tube closure end is sealed vacuum tight by means of a collar, which is attached to the process tube and against which a door rests sealingly. 
   
   
       2 . Device, as claimed in  claim 1 , wherein the collar projects beyond the process tube on a face side so that inside the collar there is a collar chamber, which can be closed in a vacuum tight manner by the door. 
   
   
       3 . Device, as claimed in  claim 2 , wherein the vacuum tight sealing of the tube closure end is carried out with the doors, applied to the rim of the collar on the face side with the interposition of a seal. 
   
   
       4 . Device, as claimed in  claim 1 , wherein the stopper is attached in a detachable and spring loaded manner to an inside of the door. 
   
   
       5 . Device, as claimed in  claim 4 , wherein the stopper is attached to the door by bayonet closure. 
   
   
       6 . Device, as claimed in  claim 1 , wherein the stopper is made of quartz, SiC or another material that is adequately temperature stable and medium resistant. 
   
   
       7 . Device, as claimed in  claim 1 , wherein the stopper is coated with quartz, SiC or another material that is adequately temperature stable and medium resistant. 
   
   
       8 . Device, as claimed in  claim 1 , wherein the door comprises aluminum. 
   
   
       9 . Device, as claimed in  claim 8 , wherein the door is water cooled. 
   
   
       10 . Device, as claimed in  claim 9 , wherein the door is provided with a cooling water inlet Hand a cooling water outlet for the through passage of a coolant. 
   
   
       11 . Device, as claimed in  claim 10 , wherein a ring-shaped groove in the door is provided for distribution of the coolant. 
   
   
       12 . Device, as claimed in  claim 2 , wherein the door His provided with a flushing gas inlet for introducing a flushing gas into the collar chamber and exhibits includes a flushing gas outlet. 
   
   
       13 . Device, as claimed in  claim 12 , wherein the flushing gas outlet is connected by way of a hose line to a gas conveying tube and a pump for pumping the flushing gas out of the collar chamber and for pumping the process gases out of the process chamber. 
   
   
       14 . Device, as claimed in  claim 13 , wherein the gas inlet is connected to a source for nitrogen. 
   
   
       15 . Device, as claimed in  claim 2 , wherein the collar chamber exhibits an overpressure in relation to the process chamber in the process tube. 
   
   
       16 . Device, as claimed in  claim 15 , wherein a pressure differential ranges from zero to approximately 50 mbar. 
   
   
       17 . Device, as claimed in  claim 2 , further comprising a common pump for evacuating the process chamber and the collar chamber and for generating a pressure differential between the process chamber and the collar chamber. 
   
   
       18 . Device, as claimed in  claim 17 , wherein for the purpose of generating the pressure differential, the connection of the collar chamber to the pump comprises a line that is long in comparison to a process tube extraction and which exhibits a smaller cross section. 
   
   
       19 . Device, as claimed in  claim 17 , wherein a cooling trap is disposed upstream of the pump. 
   
   
       20 . Device, as claimed in  claim 17 , wherein the pump is comprises a diaphragm pump, screw pump or jet pump. 
   
   
       21 . Device, as claimed in  claim 18 , wherein, in order to form the pressure differential, a suitable leak rate of a contact point of the stopper and the sealing rim of the process tube is set by a flat finish of surfaces that meet. 
   
   
       22 . Device, as claimed in  claim 1 , wherein a process gas outlet for carrying away the process gases is located on an end of the process tube that lies opposite the tube closure. 
   
   
       23 . Device, as claimed in  claim 22 , wherein the process gas outlet is provided with a spherically ground joint. 
   
   
       24 . Device, as claimed in  claim 22  wherein the process gas outlet is either downwardly sloped or horizontal. 
   
   
       25 . Device, as claimed in  claim 24 , wherein the process gas outlet is sloped downwardly by approximately 5 degrees. 
   
   
       26 . Device, as claimed in  claim 22 , wherein a spherically ground joint won the gas outlet is configured for attachment and for through passage of a gas outlet lance ( 18 ). 
   
   
       27 . Device, as claimed in  claim 2 , wherein the collar chamber is evacuated by a gas conveying tube via a T-piece, through which the gas conveying tube is run. 
   
   
       28 . Device, as claimed in  claim 1 , wherein process gas inlet into the process chamber by coaxial tube as a component of a gas inlet lance takes place on a side of the process gas outlet that extends as far as up to the stopper on an other side of the process tube without touching said stopper.