Determination of 2D implanted ion distributions using inverse radon transform methods

Two methods are presented for the experimental determination of 2D implanted ion distribution resulting from implantations with a line source into amorphous targets. It is shown that the relation between the 2D distribution and the depth profiles resulting from tilted angle implantations is described by the Radon transformation. The inverse transformation has been applied to accurately measured depth profiles. The first method uses a digitization of the 2D distribution and the second method uses a parameterized function for the 2D distribution. The methods are tested for a 400 keV boron implantation in an amorphous layer of silicon. The experimental obtained 2D distributions are compared with a TRIM Monte Carlo simulation. A good agreement between experiment and simulation is observed

Two methods to improve the performance of Monte Carlo simulations of ion implantation in amorphous targets

Two methods are described for improving the results of a Monte Carlo technique used to simulate the transport of energetic ions in amorphous targets in two dimensions. The target considered is a homogeneous monolayer. The Monte Carlo technique used is based on the TRIM program. The first method relies on the fact that some calculated data can be used more than once. The second method relies on the fact that a point source results in a rotation-symmetric ion distribution. To study the behaviour of the two methods a smoothness indicator was defined. It is a measure of the distance of a simulation result from the ideal result, i.e., the result based on an infinite number of ion trajectories. This indicator showed that a CPU time reduction of a factor of 80 was achieve