Laser Infrared Photothermal Radiometric and ELYMAT Characterizations of p-Si Wafers Annealed in the Presence of an External Electric Field

Abstract

Subject classification: 72.20.Jv; 73.40.Mr; S5.11 Laser infrared photothermal radiometry (PTR) was used as an analytical technique to measure the electronic transport parameters of p-Si wafers oxidized and thermally annealed under positive or negative external bias applied to the back surface. It was found that, following Fe contamination and recombination lifetime t e , degradation in the oxidation and thermal-anneal furnace, both polarities of the external field result in significant minority carrier lifetime improvement, as well as in strong changes in the front-surface recombination velocity S 1 , of the samples, compared to a zerobias annealed reference sample. A qualitative model involving the passivating action of positive mobile ions (protons) trapped at the oxide-Si interface was advanced to explain the relative relations S 1 (+) > S 1 (0) > S 1 (--) . The lifetime relations t e (+) > t e (--) > t e (0) obtained through both PTR and electrolytical metal tracer (ELYMAT) measurements were explained in terms of the relative abilities of positive and negative applied electric fields to prevent heavy metal ions from diffusing into the Si bulk and compromising the lifetime.

Infrared photocarrier radiometry of semiconductors: Physical principles, quantitative depth profilometry, and scanning imaging of deep subsurface electronic defects

“…In recent years the development of laser-induced infrared photothermal radiometry ͑PTR͒ of semiconductors in our laboratory [1][2][3][4][5][6][7][8][9] and elsewhere 10 as a quantitative methodology for the measurement of transport properties of semiconductors has led to several advances in the noncontact measurement of four transport parameters: bulk recombination lifetime, ͑two͒ surface recombination velocities, and carrier diffusion coefficient in Si ͑Refs. 1-10͒ and GaAs ͑Ref.…”