Characterization of B and Sb delta-doping profiles in Si and Si1−xGex alloys grown by molecular-beam epitaxy

Abstract

Boron and antimony deltalike doping spikes in Si and Si1−xGex layers with x=0 to x=0.25 deposited by molecular-beam epitaxy (MBE) have been investigated as candidates for p and n delta- doping MBE technology. They were characterized by high depth resolution secondary ion mass spectrometry (IMS) measureements using oxygen and cesium primary ion beams in the energy range from 2 to 12 keV and by high depth resolution spreading resistance measurements. Deltalike doping profiles with a full width at half-maximum of less than 2.7 and 3 nm have been measured by SIMS for Sb and B, respectively, with corresponding upward slopes of 0.4 and 1 nm. For Si1−xGex growth segregation effects, the electrical activity of B decreases with increasing Ge content, and the steepness of the B spikes increases. The behavior of B spikes during annealing is investigated.