Awafer-level, heterogeneously integrated, high flow SMA-silicon gas microvalve

This paper presents a novel gas microvalve design in which a flow control gate is opened by the pneumatic pressure and closed by a SMA actuator, allowing large flow control. The microvalves were fabricated using a novel wafer-level Au-Si eutectic bonding process for TiNi to silicon integration. The resulting microvalves demonstrate a record pneumatic performance per footprint area; a microvalve of only 1×3.3 mm² footprint successfully controls 3000 sccm at a pressure drop of 130 kPa.