A multilayer fluidic laminar proportional amplifier (LPA) was fabricated from silicon wafers by using state-of-the-art photolithography and silicon deep-reactive ion-etching (DRIE) technologies. The assembled silicon amplifier showed a factor of 10 improvement in null offset when compared to an amplifier fabricated with traditional stainless steel laminates. Null offset is a measure of fabrication quality.
The pressure gain, which is a measure of performance, of the silicon amplifier was lower than expected. The low gain values resulted from a more faithful fabrication of the selected LPA design in silicon, producing a constricted flow condition. The same condition did not exist in the traditional stainless steel amplifier because patterning and overetching of the control features during photochemical milling widened the gap between the control edges beyond the designed value. The fabrication capability of the DRIE process has forced a reevaluation of the current LPA design.