A novel high-resolution technique for the study of deep energy levels in semiconductors based on computerized Laplace-DLTS

Abstract This paper describes a new computerized system for investigating deep levels in semiconductors by DLTS. We used a modified measurement mode, a new approach based on the inverse Laplace transform, and a new data processing algorithm. The developed method uses only a few transients derived and averaged from DLTS measurements at heating rates up to 2 °C/min, combined with low-frequency pulses. The paper presents data obtained for a phosphorus-doped silicon PIN diode, previously investigated using a conventional computerized DLTS system. Our new method allowed us to detect three electronic levels with energies of Ec – 0.53 eV, Ec – 0.39 eV, and Ec – 0.38 eV in less than 1 h, while the conventional DLTS system detected only two levels: Ec – 0.53 eV and Ec – 0.42eV. Thus, we have shown that the new approach drastically reduces the measurement time and increases the resolution.