Characterization of the Two-Photon Absorption Carrier Generation Region in Silicon Diodes

Abstract

Two-photon absorption (TPA) has become an important tool for understanding the mechanisms of single-event effects (SEE) in microelectronics. Very little experimental work has been reported that describes the physical structure of the charge cloud centered on the focal plane where TPA carrier generation is likely to occur (the "TPA region"). A detailed study of the TPA region would provide valuable insight into the use of TPA as an SEE testing method in general. This work reports measurements of the spatial extent of the TPA region in the direction of beam propagation in silicon diodes. Experimental results indicate that the waist diameter of the beam can have a significant impact on the spatial qualities of the TPA region and that in some circumstances, peak charge collection occurs when the focal plane of the laser is several micrometers below the junction. The implications that these results could have for TPA SEE laser testing will also be discussed. A simple analytical model for TPA in a semiconductor is implemented using device level simulations. Results indicate that while the simple model is adequate for describing qualitative trends, it is not suitable for quantitative studies.