Electronic transport characterization of B+ ion-implanted silicon wafers with nonlinear photocarrier radiometry

Abstract

A nonlinear photocarrier radiometry (PCR) based quantitative defect characterization method is applied to determine the electronic transport parameters of the implantation layer of B+ ion-implanted silicon wafers with different implantation doses. A rigorous two-layer nonlinear PCR model is employed to fit the experimental modulation frequency dependences of PCR amplitude and phase to determine the transport parameters, that is, the carrier lifetime, carrier diffusion coefficient, and front surface recombination velocity of the implantation layer via multiparameter fitting. In the multiparameter fitting, the effects of the implantation layer thickness determination on the extraction of the electronic transport properties of the implantation layer are discussed via setting the thickness as a free parameter in the multiparameter fitting and fixed parameters determined by Monte Carlo based TRIM calculation. The fitted implantation layer thicknesses are in good agreement with that determined via TRIM calculation with a modified electronic damage threshold. Monotonic dependences of the transport properties of the implantation layers on the implantation dose are observed, and the effects of impurity density on the transport properties of the implantation layers are discussed. Good agreements between the experimental implantation dose dependence of the nonlinearity coefficient and corresponding theoretical calculations with the determined transport parameters are obtained. These results show that the two-layer nonlinear PCR model is accurate for quantitatively characterizing the transport properties and thickness of the ion-implantation layers of silicon wafers, and the nonlinear PCR technique is appropriate for precise defect characterization in the semiconductor manufacturing processes.

Differential nonlinear photocarrier radiometry for characterizing ultra-low energy boron implantation in silicon

“…[18] The implanted layer is generally composed of the region traversed by the implanted atoms and the region in which the atoms eventually reside, and its thickness is generally defined as the distance between the wafer surface and the internal intersection between the electrical damage threshold and the impurity concentration depth profile due to the much higher sensitivity of electronic properties to the activation degree of implanted atoms and crystalline damage as the much higher sensitivity of electronic properties to the activation degree of implanted atoms and crystalline damage. [19,20] According to the calculated electrical damage threshold (Y ED ) of the boron-implanted silicon wafer with a Y ED of 5.3×10 15 cm −3 , [21,22] the determined thickness values of the shallow junction are listed in Table 1. The results indicate that the lower the implantation energy, the shallower the formed junction is.…”