Hole confinement in boron delta -doped silicon quantum wells studied by deep-level transient spectroscopy.

Abstract

Observation of the hole-confinement effect in boron \ensuremath{\delta}-doped Si quantum wells has been demonstrated using the deep-level transient spectroscopy (DLTS) technique, based on the concept of treating the quantum well as a big ``trap.'' For the same doping thickness but different doping densities, i.e., different boron sheet doping concentrations, the well depths and the subband positions are different and the peak shift of DLTS spectra is thus expected and is observed experimently for two samples with sheet doping concentrations of about 2.4\ifmmode\times\else\texttimes\fi{}${10}^{13}$ and 6.0\ifmmode\times\else\texttimes\fi{}${10}^{13}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$, respectively. A self-consistent calculation of the subbands in the quantum wells verifies that the detected activation processes in DLTS correspond to the hole emissions from the hole ground states in the \ensuremath{\delta}-doped quantum wells to the top of the wells. \textcopyright{} 1996 The American Physical Society.