Ultrafast diffusion of a defect in indium-doped silicon introduced by chemomechanical polishing

Abstract

The deactivation of the acceptor indium after chemomechanical polishing of p-type silicon is shown to result from the formation of a complex involving the indium atom and a positively charged, extremely fast-diffusing defect X. In the temperature range from 220 to 280 K, the dissociation frequency ν of this complex and the diffusion coefficient D of the defect X are thermally activated and satisfy the expressions ν=ν0 exp(−Ed/kT) and D=D0 exp(−Ea/kT) with ν0=2.6×1012 s−1, Ed=0.690 eV, D0=5×104 cm2/s, and Ea=0.665 eV.

Hydrogenation of the CuPL center in silicon

“…The low-temperature CV profiling after the reverse-bias cooling (similar to Ref. 7) shows that concentrations of the mobile Cu i species and their complexes with boron in the analyzed region are below the estimated detection limit of $2 Â 10 13 cm À3 . At the same time, the net boron concentration is significantly reduced closer to the surface indicating the presence of hydrogen introduced during the sample preparation.…”

“…3,6 In particular, Cu i 's can be introduced into silicon wafers in a controllable way by chemomechanical polishing in a Cu-contaminated slurry at room temperature. 7 In this case, formation of the Cu PL center was observed to proceed via two intermediate deep-level complexes, each including one Cu s atom. 8 All these experimental findings lead to the conclusion that the Cu PL complex consists of a Cu s core decorated with three Cu i atoms.…”

Impact of Research on Defects in Silicon on the Microelectronic Industry

“…Collaboration between industry and universities was at work, too in uncovering the puzzle of Cu contamination during chemomechanical polishing [42,43]. It was discovered in polishing experiments on highly boron-doped Si that a transient passivation behavior by in-diffusion of Cu can occur even near room-temperature with an estimated diffusion rate of about 10 ± ±7 cm 2 /s which was several orders of magnitude larger than extrapolated from high temperature data.…”

Copper in silicon

“…5) or an intrinsic defect. 12 Also Prescha et al recently proposed the identification of A' as a Curelated defect on the basis of capacitance-voltage experiments. ,3 By the same technique, the thermal stability of the \n-X complexes was determined yielding ££>=0.69 eV and 2.6xl0 12 s -1 as the attempt frequency 12 in agreement with the data of Fig.…”