A quick method to realize and characterize bimorph cantilevers

Bimorph cantilever-based thermal actuators are promising for numerous applications like micro-mirror arrays, etc. This paper presents a simple technique for fabricating bimorph cantilevers using a single photolithography process and a quick optical methodology for the characterization of such structures. A bimorph combination of Al-SiO₂ has been realized where SiO₂ cantilevers are first realized, followed by aluminum sputtering to make the desired bimorph structure. Silicon oxide cantilevers are defined using optical photolithography, silicon area exposed by etching SiO₂ in buffered oxide etch (BOE) solution and structures are released by wet bulk micro-machining of silicon in 25% TMAH solution. The cantilever deflection is characterized in a temperature range of 24-56°C using external heating and the corresponding deflections recorded via 3D imaging. A 97 μm-long cantilever tip shows a deflection of ~3.7 μm, when its temeprature changes by 32°C, corresponding to an actuation of 2.1 degrees.