Transport spectroscopy of the ultrasmall silicon quantum dot in a single-electron transistor

We investigate electron transport through the ultrasmall silicon quantum do t in a single-electron transistor. The device is fabricated in the form of a silicon point-contact channel metal-oxide-semiconductor field-effect tran sistor. The size of the formed dot is estimated to be as small as 5.3 nm. N egative differential conductance is clearly observed up to 25 K. It turns o ut that this is caused by discreteness of quantum levels in the silicon dot and variation of the tunneling rates to each level. The fine structure of conductance persists up to 77 K. Modeling of the electron transport through the silicon dot is carried out. Good agreement between experiment and calc ulation is obtained, which confirms the validity of our model. (C) 2001 Ame rican Institute of Physics.