Analysis of X-ray rocking curves in (0 0 1) silicon crystals implanted with nitrogen by plasma immersion ion implantation

Abstract

High-resolution X-ray diffraction methods have been used to characterize nitrogen-doped silicon obtained by plasma immersion ion implantation (PIII). The Si wafers were implanted with the plasma potential controlled at 70 V, and a plasma density of 1.5×10 10 cm −3. The high voltage pulser was operated with peak voltage of 10 kV, 6 μs pulse duration and repetition frequency of 20 Hz. Auger electron spectroscopy (AES) measurements were carried out revealing successful implantation of ions with accumulated nitrogen dose of 1.5×10 17 cm −2. The (0 0 4) Si rocking curve (ω-scan) was measured in a high resolution X-ray diffractometer equipped with a Ge(2 2 0) four crystal monochromator before and after implantation. A small distortion of the Si(0 0 4)-rocking curve was clearly observed for the as-implanted sample. This rocking curve was simulated by dynamical theory of X-ray diffraction, assuming a Gaussian strain distribution through the implanted region and using the data from the nitrogen profile obtained from the Auger measurements. With these assumptions, a good agreement between the measured and simulated rocking curves was obtained.