Diffusion of gold into plastically deformed undoped and boron-doped silicon

Diffusion of Au into highly dislocated Si monocyrstals undoped and uniformly boron-doped with a B concentration of C_B=3×10 ¹⁹ cm^-3 has been investigated with the aid of neutron-activation analysis (NAA) in conjunction with mechanical sectioning. Au profiles produced at diffusion temperatures of 900°C, 1000°C and 1100°C show Au diffusion to be enhanced in heavily B-doped Si compared to undoped samples. The profiles are completely described within the framework of the kick-out model and a mechanism which accounts for dislocation induced Au trapping. On the basis of these diffusion mechanisms Au profiles yield data for the transport capacity C_Aui ^eq D_Aui of interstitial Au. Data deduced for intrinsic conditions are consistent with corresponding results obtained by Au diffusion in dislocation-free Si under isoconcentration conditions. The observed doping dependence of C _Aui ^eq D_Aui shows that A_ui diffuses as a singly positively charged impurity in p-type Si which introduces a donor level at about 0.48 eV above the valence-band edge.