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We report a study of temperature dependence of electron resonant tunneling diodes in an Si/Si1−xGex material system grown by rapid thermal chemical vapor deposition. Up to four highly symmetric resonances were observed, but the lowest energy resonance has an anomalous temperature behavior, decreasing in strength with decreasing temperature below 140 K and entirely disappearing below 50 K. The temperature behavior and bias position of the resonance are consistent with a model of phonon-absorption-assisted tunneling with a phonon energy of 14±2 meV. The phonon is thought to be an acoustic phonon which promotes Umklapp scattering between the conduction band minima in the emitter and quantum well states.

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We report the fabrication of symmetric, n-type resonant tunneling diodes grown by rapid thermal chemical vapor deposition in the Si/Si1−xGex material system. Up to four resonant features were observed for both positive and negative bias. This is the first time that such highly symmetric features are reported for electron resonant tunneling in the Si/SiGe material system. A peak-to-valley ratio of 2 was achieved at a temperature of 4 K and resonances were observed up to 240 K. An additional peak is observed at low voltages exhibiting an anomalous temperature behavior, disappearing at temperatures below 50 K. Models involving phonon absorption or emitter quantization are proposed to explain this behavior.