Atomic deuterium passivation of boron acceptor levels in silicon crystals

Abstract

B-doped Si wafers were subjected to atomic-deuterium (D) plasmas to simulate the reactions of atomic hydrogen with substitutional B acceptor levels. Secondary ion mass spectrometry was used to profile the in- and out-diffusion of D, and spreading resistance was used to measure the distribution of net acceptor levels after deuteration and subsequent thermal annealing. A direct correlation was found between passivation of B acceptors and the presence of atomic deuterium. The passivated acceptor levels can be restored by thermal annealing above 200 °C. In addition, B enhances the production of another D-containing species, possibly molecular D2, which is not readily removed from crystalline Si below 400 °C. These results are contrasted to other reports of interaction of atomic H with p-type dopants, as well as with structural and chemical defects.