Sub-100 nm patterning of GaAs using in situ electron beam lithography

Patterning of GaAs at the sub-100 nm size has been demonstrated using in situ electron beam (EB) lithography processes. Patterning is carried out by EB exposure of an ultrathin oxide layer on GaAs which is used as a mask material. The patterns are transferred into GaAs by Cl2 gas etching. A high-brightness Schottky electron gun is used in the exposure process. The size of the etched feature is as small as 50 nm, which is equal to the diameter of the electron beam. The results show that in situ EB lithography processes using an ultrathin oxide mask are very promising for fabricating nanometer-scale structures.