| Popis: |
Knowledge of the lateral or spatial distribution of doping impurities is important for accurate process and device simulations of submicrometer silicon devices, since the edge effects of the electric fields can no longer be neglected. A newly developed technique, which utilizes the high sensitivity and high depth resolution of secondary ion mass spectrometry (SIMS), is capable of measuring two‐dimensional (2D, i.e., in the depth and the lateral direction) doping distributions. The technique is based on a series of one‐dimensional (1D) SIMS depth profiles obtained at different directions through a sample. The individual SIMS depth profiles are then recombined to generate a 2D doping profile using the expectation maximization algorithm, which was originally used in human body computer‐aided tomography. The SIMS tomography technique gives a doping distribution as a function of position. The positional accuracy or spatial resolution of the technique needs to be fully understood in order to properly use the te... |
