Fabrication and First Characterization of Silicon-Based Full 3-D Microdosimeters

Microdosimetry provides measurements of stochastic lineal energy deposition in a micrometric sensitive volume (SV) that are comparable to human cell dimensions, typically in the order of 10-15 mu m in diameter. Silicon-based microdosimeters have been fabricated using 3-D technology, providing true cell-like SVs that are fully encapsulated by a 3-D through substrate electrode. The unique geometry has been made feasible using modern microelectromechanical systems (MEMS). The combination of MEMS techniques and radiation detector fabrication brings forth challenges in achieving reliability, consistency, and high yield. This article reviews the technological challenges encountered in several prototype runs completed at SINTEF. The technological review and prototype iterations aim to deliver a future technology plan at the manufacture level with a high yield throughput.