Plasma shallow doping and wet removal of depth control cap

Abstract

A gas is ionized into a plasma. A compound of a dopant is mixed into the plasma, forming a mixed plasma. Using a semiconductor device fabrication system, a layer of III-V material is exposed to the mixed plasma to dope the layer with the dopant up to a depth in the layer, forming a shallow doped portion of the layer. The depth of the dopant is controlled by a second layer of the dopant formed at the shallow doped portion of the layer. The second layer is exposed to a solution, where the solution is prepared to erode the dopant in the second layer at a first rate. After an elapsed period, the solution is removed from the second layer, wherein the elapsed period is insufficient to erode a total depth of the layer and the shallow doped portion by more than a tolerance erosion amount.

1 . A computer usable program product comprising one or more computer-readable storage devices, and program instructions stored on at least one of the one or more storage devices, the stored program instructions comprising:
 program instructions to ionize a gas into a plasma;   program instructions to mix a compound of a dopant into the plasma, forming a mixed plasma;   program instructions to expose, using a semiconductor device fabrication system, a layer of III-V material to the mixed plasma to dope the layer with the dopant up to a depth in the layer, forming a shallow doped portion of the layer;   program instructions to control the depth of the dopant by a second layer of the dopant formed at the shallow doped portion of the layer;   program instructions to expose the second layer to a solution, the solution prepared to erode the dopant in the second layer at a first rate; and   program instructions to remove, after an elapsed period, the solution from the second layer, wherein the elapsed period is insufficient to erode a total depth of the layer and the shallow doped portion by more than a tolerance erosion amount.   
     
     
         2 . The computer usable program product of  claim 1 , further comprising:
 program instructions to compute, using a processor and a memory, the elapsed period as a function of the temperature.   
     
     
         3 . The computer usable program product of  claim 2 , wherein the function is an inverse relationship function. 
     
     
         4 . The computer usable program product of  claim 1 , wherein the computer usable code is stored in a computer readable storage device in a data processing system, and wherein the computer usable code is transferred over a network from a remote data processing system. 
     
     
         5 . The computer usable program product of  claim 1 , wherein the computer usable code is stored in a computer readable storage device in a server data processing system, and wherein the computer usable code is downloaded over a network to a remote data processing system for use in a computer readable storage device associated with the remote data processing system. 
     
     
         6 . The computer usable program product of  claim 1 , wherein the solution is heated to a temperature. 
     
     
         7 . The computer usable program product of  claim 6 , wherein the temperature is in a range that includes sixty degrees Celsius. 
     
     
         8 . The computer usable program product of  claim 1 , wherein the solution comprises Tetra Methyl Ammonium Hydroxide (TMAH) that has been diluted to a ratio. 
     
     
         9 . The computer usable program product of  claim 8 , wherein the ratio is a percentage range that includes twenty-five percent. 
     
     
         10 . The computer usable program product of  claim 1 , further comprising:
 program instructions to adjust an amount of time the layer is exposed to the mixed plasma to adjust an amount of the dopant in the second layer.   
     
     
         11 . The computer usable program product of  claim 1 , further comprising:
 program instructions to deposit, using the mixed plasma, the second layer of the dopant over the doped portion of the layer.   
     
     
         12 . The computer usable program product of  claim 1 , further comprising:
 program instructions to adjust an amount of the compound mixed into the plasma to adjust a speed of depositing the second layer.   
     
     
         13 . The computer usable program product of  claim 1 , wherein the shallow doped portion increases an electron mobility in the layer up to a threshold level. 
     
     
         14 . The computer usable program product of  claim 1 , further comprising:
 program instructions to remove, as a part of the exposing the layer to the mixed plasma, oxygen from an oxide molecule in the layer, wherein the removing the oxygen causes the dopant to reach the depth.   
     
     
         15 . The computer usable program product of  claim 1 , wherein the dopant is Silicon, and wherein the compound is Silane. 
     
     
         16 . The computer usable program product of  claim 1 , wherein the gas is one of Argon and Helium.