Thin film shape memory microvalves with adjustable operation temperature

Abstract Gas microvalves of about 3×3×5 mm 3 size are presented, which are actuated by a microdevice of shape memory alloy (SMA) thin film with stress-optimized shape. By variation of the chemical composition of the material system Ti–Ni–Pd, the phase transformation temperatures have been adjusted in a range below 405 K in order to design the operation temperature of the valves. The main fabrication technologies were magnetron sputtering and electrolytic photoetching of the thin films and hybrid integration of the valve components. The SMA microvalves work in a normally open mode and allow control of pressure differences below 2500 hPa at gas flows below 360 standard ccm (sccm).