DIFFUSION LENGTH EVALUATION OF BORON-IMPLANTED SILICON USING THE SEM-EBIC-SCHOTTKY DIODE TECHNIQUE

The SEM operated on the EBIC model is used to evaluate the diffusion length in p-type silicon implanted with 400 kV boron ions to a dose of 1014 B+ cm-2 and annealed to temperatures in the range 700-1000 degrees C. The method is to fabricate a Schottky diode on the irradiated surface of the implanted sample, and then place the sample in the SEM in such a way so that the beam is incident normal to the sample surface partly covered with the Schottky diode metal film; the diffusion length is found by slowly scanning the beam away from the Schottky diode and analysing the resulting EBIC decay. It is found that the effect of the implantation is to reduce the diffusion length with reference to an unimplanted sample subjected to the same heat treatment. The reduction is approximately 53% at 700 degrees C, and as the annealing temperature increases it gradually decreases to approximately 21% at 1000 degrees C. This shows that the effect of the damage on the diffusion length decreases with increasing annealing temperature.