10/sup 5/ times biasing current improvement in an electron wave interference device with vertical superlattices

The authors have fabricated a novel WBT (washboard transistor) with an (AlAs)/sub 1/4/ (GaAs)/sub 3/4/ vertical superlattice. The vertical superlattice (FLS) has a 10-nm-order periodicity perpendicular to the growth direction. The FLS improves the WBT's biasing current by about 10/sup 5/ times compared to the previous WBT with a 500-nm grating gate. The modulation-doped AlGaAs/GaAs heterojunction structure with FLSs is grown on [001]-oriented semi-insulating GaAs substrate with a misorientation angle of 1.0 degrees toward the [110] direction. The electron concentration is about 10/sup 3/ larger than that of the previous WBT, resulting from periodicity reduction from 500 to 16.2 nm.