Observation of dopant-vacancy defects by low-frequency noise measurements in heavily doped n+/p+ silicon diodes

Low-frequency noise measurements have been performed at several temperatures for reverse biased silicon diodes heavily doped on both sides. The dopant impurities were boron and phosphorus. The analysis of the generation-recombination components of the noise spectrum showed two trap levels with an activation energy of 0.35 and 0.45 eV. These are typical of two defect complexes: the boron-vacancy pair and the phosphorus-vacancy pair, respectively. In spite of limited accuracy in the determination of activation energies, low-frequency noise measurements can therefore be used to detect such defect complexes, which can play an important part in understanding the diffusion in heavily doped silicon. Low-frequency noise spectroscopy appears to be the simplest technique available to measure such defects in silicon. (C) 1998 Elsevier Science Ltd. All rights reserved.