SIMS Quantitative Analysis of Gallium in Silicon by Using Ion-Implanted Samples for Standards

Ion-implanted samples are generally used as SIMS impurity analysis standard materials for semiconductor devices. However, che accuracy of the calibration has not been so clear. The impurity concentration is generally determined by using the Relative Sensitivity Factor, RSF value. RSF value is determined from the relation between the ion implantation dose and the integrated value of secondary ion signals. There are various error factors in this calibration method. One of them is che accuracy of the ion dose. Another one is the error related to depth profiling. Errors due to depth profiling are mainly 1) lack of accuracy of the depth measurement, 2) non-uniform sputtering, 3) the variation of secondary ion yield and 4) cascade mixing and radiation-enhanced diffusion. The depth measurement error can be decreased to a very small value by careful experiment. However, other errors have originated in SIMS fundamental phenomena and not easily decreased. In this reporc these errors are investigated in detail for gallium in silicon.