Deep levels of vanadium and vanadium-hydrogen complex in silicon

Deep levels in vanadium-doped n- and p-type silicon have been investigated using deep level transient spectroscopy (DLTS) and concentration profile measurements. The DLTS measurement reveals two electron traps of E _C-0.20 eV and E_C-0.45 eV, and a hole trap of E _V+0.34 eV. These three levels correspond to the transitions between four charge states of interstitial vanadium. Furthermore, an electron trap of E_C-0.49 eV is observed near the surface region of n-type samples etched with an acid mixture containing HF and HNO₃. The origin of the trap has precisely been investigated by isochronal anneals and various chemical treatments. From these investigations, it is found that the trap is due to a complex of interstitial vanadium with hydrogen introduced by chemical etching.