Defect profiles in B or P implanted Ge after Flash Lamp Annealing probed by Slow Positron Implantation Spectroscopy

B+ and P+ ions were implanted into Ge wafers covered with an amorphous surface layer of 150 nm. After this, FLA in Ar atmosphere was used in order to realise three objectives:

• recrystallisation of the amorphous region on top of the Ge wafer
• electrical activation of the implanted ions
• reduction of diffusion processes during the FLA.

The heat treatment with Xenon flash lamps having a spectrum in the visible range of light and a pulse length of 3 or 20 ms allowed an ultra-short heating up of the near surface region. In this way, a modification of the structure of the amorphous layer containing the implanted range was possible. Depth profiles of defects, especially of the vacancy-type, were investigated by SPIS before and after FLA.
It will be shown that the remaining vacancy-type defect structure depends on the parameters of the process of heat treatment, and that these defects could not be completely removed by FLA.
These results will be compared with such from SRIM 2003 calculations (Stopping and Range of Ions in Matter) and Rutherford Backscattering Spectrometry.