Mev He Ion Implantation in Si Wafers
EMSL Project ID
2044
Abstract
The aim of this proposed work is to probe the inter-defect distribution (IDD) model that relates the phonon correlation length to the ion dose received by a material such as silicon. Previous workers have found that the phonon correlation length is inversely proportional to the cube root of the ion dose received. The defects are assumed to be point defects, uniformly distributed in 3 dimensions. The IDD model suggests that the relevant correlation length is a function of the mean size of the defect-free region, which indeed should decrease when the ion dose increases. Those studies used a model that fitted the measured Raman lineshape, and which assumed a spherical defect-free region. However, this model does not take into account the possibility that the implanted ions have left a trail of damage on their way into the material, which in reality results in a complicated defect distribution. Reviewing the work previously published, we think important to develop the analysis technique further, so we would like to propose the use of different experimental parameters and a different model that assumes columnar regions of defect-free material. We would like to use the ion implantation facilities at PNNL to create a sample with damage running normal to the surface of the thin film. Because of relative high energies (1-3 MeV), the mean stopping distance for ions should be larger than the mean probe depth of the Raman experiments; sufficiently large ion energies should be used to guarantee this. Working from the ion dose per unit area, the mean radius of the damage-free cylinders may be calculated, and compared to the results derived from a fitting program that analyzes the Raman intensity and extracts a correlation length.
Project Details
Project type
Exploratory Research
Start Date
2000-08-08
End Date
2003-07-08
Status
Closed
Released Data Link
Team
Principal Investigator