Silicide-based release of high aspect-ratio microstructures

A new method for releasing high aspect-ratio microstructures has been demonstrated that utilizes silicidation to form gaps between movable microstructures and their substrates in substantially faster times than conventional sacrificial layer-based release methods and with much less concern for stiction or attack of unintended layers. The key enabling element is the use of a self-sufficient chemical reaction (such as silicidation) to provide volume shrinkage that then induces a gap between surfaces involved in the reaction. Using this silicide-based approach, 260:1 aspect-ratio gaps have been released in less than 2 minutes, which is much shorter than the 40 minutes or more that would otherwise be required by wet-etching. This silicidation-based approach to releasing microstructures greatly increases the achievable lateral dimensions of etch hole-free suspended microstructures and stands to substantially lower the time and cost required to produce such structures.