Electronic and vibrational properties of interstitial clusters in degenerately boron-doped silicon [dataset]

Degenerate boron-doped silicon is prone to interstitial clustering, which adversely impacts key electrical properties, such as carrier concentration and mobility. Clustering becomes increasingly important with device miniaturisation, due to the high boron concentrations involved. Here we use vibrational and Compton electron energy loss spectroscopy (EELS) in a (scanning) transmission electron microscope to measure changes in the vibrational and electronic properties of the silicon host lattice due to degenerate boron doping (1020 cm−3 hole concentration). A broad phonon defect band centred at 1064 cm−1 wavenumber was detected. Subtle changes in bonding anisotropy due to boron doping along [110] and [100] directions were also observed. Density functional theory (DFT) modelling showed that boron acceptors had very little effect on the phonon and bonding properties. Instead boron interstitial clusters two to three atoms in size produced changes that agreed more closely with experiment. The results suggest the potential of using high spatial resolution EELS for the detection of clustering phenomena at the device level.