| The continuing device miniaturization in silicon technology to the nanoscale regime opens new avenues for Si-integrable quantum tunneling devices. This thesis describes our study of three novel Si-based tunneling devices: The multiemitter tunneling heterojunction bipolar transistor (MT-HBT), the lateral interband tunneling transistor (LITT) and the ultrathin silicon-on-insulator (SOI) vertical tunneling transistor (VTT).; In the Si/SiGe npn MT-HBT, interband tunneling in a heavily doped, reverse biased emitter-base junction supplies the controlling current, while the other forward biased emitter injects the collector current. Despite the lack of a true base contact, the device operates as a normal HBT with high current gain, and the emitter symmetry leads to logic functionality in a single device. Interband tunneling in silicon, which has an indirect bandgap, requires momentum transfer from either phonons or impurities and is not well understood---our devices provide an experimental testbed for existing theory.; Interband tunneling is, again, the underlying principle of our LITT devices, where the source and drain form a heavily-doped lateral pn junction in a thin Si film on an SOI substrate. We observe control of the reverse-bias tunneling current under drain bias by a gate voltage of either bias polarity. Systematic current-voltage measurements, together with numerical device simulations, show that in first approximation the drain current depends on the maximum junction electric field.; The VTT in SOI is a resonant tunneling device in a transistor geometry: carriers tunnel from the doped gate through an ultrathin gate oxide into the Si quantum well channel and are extracted laterally. The devices show good transistor characteristics when operated in standard transistor mode, and backgate modulation of the tunneling current when operated in the vertical tunneling mode at low temperature.{09}In particular, we observe structure in the gate current due to resonant tunneling into the quantized channel subbands. Improved fabrication would lead to a three terminal SOI device with dual functionality at higher operating temperatures.; Our studies described herein, present the prospect of novel device operation principles based on quantum-mechanical tunneling, without sacrificing from simple fabrication and compatibility with the dominant Si technology. |
