Spreading-resistance profiling of silicon and germanium at variable temperature

Abstract

The effect of impurity-induced lattice strain and Fermi level position on low temperature oxygen diffusion in silicon J. Appl. Phys. 109, 063532 (2011); 10.1063/1.3555625The effect of preamorphization energy on ultrashallow junction formation following ultrahigh-temperature annealing of ion-implanted silicon J. Appl. Phys. 97, 044501 (2005); 10.1063/1.1844619Profile broadening of high dose germanium implants into (100) silicon at elevated temperatures due to channelingWe have developed the concept of variable-temperature spreading-resistance profiling ͑VT-SRP͒ for the characterization of electrical active impurities or defects in semiconductor crystals. Unlike conventional SRP systems, which are exclusively operated at room temperature, our home-built VT-SRP device allows for measurements at different temperatures typically ranging from 150 to 400 K. VT-SRP is able to combine the accurate resolution of an impurity depth profile with a determination of the predominant impurity-related electronic level in the semiconductor band gap. This feature was exploited on germanium crystals with diffusion-induced gold distributions. Another application concerns the depth profile analysis of foreign elements that occur in various defect configurations. This was demonstrated on Si samples diffused with sulfur or selenium since these impurities may be present as isolated atoms as well as pairs. Given the well-known energy levels of the two S or Se configurations in Si we were able to resolve not only the shape and depth of the diffusion profile but also the ratio of isolated atoms to pairs in the diffusion zone.

Reduction of the temperature dependence of leakage current of IGBTs by field-stop design

“…The temperature dependence of the concentration of ionized deep donors C ion (T) can be calculated for a deep level using the charge neutrality equation and Fermi-statistics as shown in earlier work [3,4]. Figure 1 shows the activation ratio of ionized to neutral donors C ion /C o as a function of temperature for a deep donor with an energy level of 0.2eV below the conduction band.…”