Electrical effects of a single stacking fault on fully depleted thin-film silicon-on-insulator P-channel metal-oxide-semiconductor field-effect transistors Limitations on threshold adjustment by backgating in fully depleted silicon-on-insulator metal-oxidesemiconductor field effect transistors

We have fabricated silicon-on-insulator ͑SOI͒ transistors with an ultrathin Si channel of ϳ5 nm, tunneling gate oxide of ϳ1 nm, and 100 nm gate length. In addition to good transistor characteristics, these same devices exhibit additional functionality at low temperature. The drain current I D exhibits steps near the turn-on threshold voltage as a function of the backgate V BG bias on the substrate. When operated as a gate-controlled tunneling device, with source shorted to drain and I G originating from tunneling from the gate to the channel, we observe structure in the I G (V BG ) due to resonant tunneling into the quantized channel subbands. In the future, as SOI device fabrication improves and the buried oxide thickness is reduced, these quantum effects will become stronger and appear at lower V BG , offering the prospect of ultralarge scale integration-compatible devices with standard transistor operation or quantum functionality depending on the electrode biasing.

We have observed single-hole tunneling and Coulomb blockade in the resonant tunneling characteristics of an ultrasmall Si/SiGe strained vertical quantum dot. The current steps near the tunneling threshold are due to tunneling of the holes from the emitter to the doubly degenerate ground state of the strain-induced quantum ring in the vertical quantum dot, and the spacing of the steps gives the charging energy of the quantum ring. When a magnetic field is applied parallel to the tunneling direction, the evolution of the single-hole tunneling features reveals a cusp arising from the angular-momentum transition of the single-particle ground state of the quantum ring in the magnetic field.