Single electron spin measurements in submicron silicon field-effect transistors

Presented in this experimental work is our measurements of a single electronic spin in the gate oxide of submicron-size silicon field effect transistors.; Individual defects near the silicon and silicon dioxide interface are known to have profound effects on the transistor conduction properties. For a submicron transistor, there might be only one isolated trap state that is within a tunneling distance of the channel, and that has a charging energy close to the Fermi level. The single electron trapping by the paramagnetic spin center can be sensed though the transistor channel current. This transistor structure closely resembles to several proposed spin-based quantum computing architectures.; We have studied by the statistics and dynamics of individual defects extensively by random telegraph signal (RTS), the stochastic switching of the channel conductivity due to the trapping of single channel electrons by the defect, in both p-type and n-type MOS-FET structures with channel size ranging from 240nm x 320nm to 210nm x 10um. We have identified defects of both negative/neutral and positive charge states. We also have successfully produced interfacial defects by electrical stressing. All these work are done at below liquid helium temperature.; We have, for the first time, studied the spin properties of these individual defects. By investigating the dependence of RTS statistics on a plane magnetic field, we have identified spin states of a single electron on a defect. We also have observed possible evidence of the transition from a singlet spin state to a triplet state for a single pair of electrons. Using microwave radiation of frequencies ranging from 16--50 GHz, we have detected magnetic resonance of a single electron spin. The trap occupancy or channel current changes at the electron spin resonance condition, with a g-factor of g = 2.02 +/- 0.015.; Based on the above achievements, we have proposed a scheme for single-shot spin read-out for quantum information. A preliminary result of pulsed measurement at a very high microwave frequency is presented.