Electron resonant tunneling in Si/SiGe double barrier diodes

We report upon the fabrication and characterization of the first n-type resonant tunneling diodes in the SiGe materials system. The devices fabricated were Si/SiGe/Si/SiGe/Si double-barrier diodes, employing strain-relieved SiGe as the barrier layers surrounding pseudomorphic tensile strained Si. These devices were prepared using ultrahigh vacuum chemical vapor deposition. Negative differential conductance is observed at room temperature in these devices with a peak-to-valley ratio of 1.2. The corresponding value at 77 K is 1.5.