Bulk generation lifetime studies in semiconductor structures with nonuniform distribution of electrically active defects in silicon

Abstract

A method for investigation of bulk generation lifetime of minority carriers τ g and their profiles in semiconductor of electron devices has been developed. It is based on combined application of dynamic unsteady-state current–voltage characteristics (DUCVC) and high-frequency capacitance–voltage characteristics (HFCVC) of metal–insulator–semiconductor (MIS) structures.The main advantage of DUCVC over other methods consists in higher sensitivity to registration of generation processes, possibility of direct determination of surface potential in MIS structures and experimental simplicity. Combined application of two kinds of stated characteristics eliminates doping concentration N d from τ g analysis in case of constant N d value in semiconductor. Thus the accuracy of τ g determination increases. If the doping concentration is constant and known, τ g is obtained only from DUCVC analysis. Bulk generation lifetime profiles have been investigated in Si–SiO 2 structures after formation of an internal getter near subsurface region of silicon. Effect of hydrogen annealings on formation of defect-free zone in silicon was investigated. Nonuniform distribution of electrically active defects (EAD) in silicon has been revealed.