Patent ID: 8883645

Claim:
A method for fabricating a nanopillar field effect transistor, the method comprising: providing a semiconductor substrate; depositing a first masking material on the semiconductor substrate; defining a masking pattern on the first masking material; removing selected regions of the first masking material, based on the masking pattern, thereby exposing selected regions of the semiconductor substrate, based on the masking pattern; depositing a second masking material on the first masking material and on the semiconductor substrate; removing the first masking material and unwanted regions of the second masking material, based on the masking pattern; etching an array of nanopillars in the semiconductor substrate, based on the masking pattern; depositing silicon nitride on the semiconductor substrate and on the array of nanopillars; depositing a third masking material on the semiconductor substrate, wherein the height of the third masking material is lower than the height of the array of nanopillars, thereby covering the silicon nitride deposited on the semiconductor substrate but not covering the silicon nitride deposited on the array of nanopillars; etching the silicon nitride deposited on the array of nanopillars; removing the third masking material; oxidizing the array of nanopillars, thereby obtaining a gate oxide layer between the semiconductor substrate and a bottom side of the array of nanopillars; defining at least one source region and at least one drain region, by doping the semiconductor substrate; annealing the at least one source region and the at least one drain region; removing the second masking material; depositing metal electrodes on the at least one source region, the at least one drain region, and the top of each nanopillar of the array of nanopillars.