Fluidic bypass structures for improving the robustness of liquid scanning probes
Upon analyzing failure modes and their causes in the operation of liquid scanning probes, two main modes were identified. These failure modes can be countered by a simple design element, a microfluidic bypass channel, which is straightforward to implement in most liquid scanning probe. The bypass can be operated in dc mode when filled with liquid or in ac mode when filled with gas. Each mode allows to prevent one of the two main failure modes. Presented analytical models, engineering design considerations and experimental verification enable a swift adaption of these bypass channels approach to increase operational robustness of liquid scanning probes.