Physically Rigorous Modeling of Internal Laser-Probing Techniques for Microstructured Semiconductor Devices

The space- and time-resolved distributions of charge carriers and temperature in the interior of microstructured semiconductor devices have become accessible to measurement as a variety of internal laser probing techniques has been become available. For a comprehensive theoretical analysis of these novel characterization methods, a physically rigorous model for simulating the entire measurement process is presented in this work. Major steps are the electrothermal device simulation of the sample's operating behavior and the calculation of optical-wave propagation through the sample, the lenses, and the aperture holes. We propose a numerically efficient algorithm for simulating wave propagation in large computational domains. The decisive step is the suitable choice of the computational variables which enables a significantly coarser discretization mesh without loosing accuracy. To support the design and the optimization of the experiments, the concept of "virtual experiments" is introduced as the key strategy for a quantitative analysis of the measurement techniques. As an application example, backside laser probing is discussed. It is shown that this technique provides a large measurement range as well as an excellent spatial resolution and, therefore, constitutes a powerful characterization method for a large multitude of different microstructures.