{"id":1509,"date":"2013-07-25T18:29:24","date_gmt":"2013-07-25T18:29:24","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/?p=1509"},"modified":"2013-07-25T18:29:24","modified_gmt":"2013-07-25T18:29:24","slug":"contact-printed-mems-membranes","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/contact-printed-mems-membranes\/","title":{"rendered":"Contact-printed MEMS Membranes"},"content":{"rendered":"

It is desirable to extend the functionality of MEMS to different form factors including large-area arrays of sensors and actuators, and to various substrate materials, by developing a means to fabricate large-area suspended thin films. Conventional photolithography-based MEMS fabrication methods limit the device array size and are incompatible with flexible polymeric substrates[1<\/a>]<\/sup>[2<\/a>]<\/sup>.<\/p>\n

A new method for additive fabrication of thin (125\u00b115-nm-thick) gold membranes on cavity-patterned silicon dioxide substrates using contact-transfer printing is presented for MEMS applications. The deflection of these membranes, suspended over cavities in a silicon dioxide dielectric layer atop a conducting electrode, can be used to produce sounds or monitor pressure. The fabrication process employs a novel technique of dissolving an underlying organic film using acetone to transfer membranes onto the substrates. The process avoids fabrication of MEMS diaphragms via wet or deep reactive-ion etching, which in turn removes the need for etch-stops and wafer bonding. Membranes up to 0.78 mm2<\/sup> in area are fabricated, and their deflection is measured using optical interferometry. The membranes have a maximum deflection of about 150 nm across 28-\u03bcm-diameter cavities, as shown in Figure 1[3<\/a>]<\/sup>. Using the membrane deflection data, Young\u2019s modulus of these gold films is extracted (74\u00b117 GPa), and it is comparable to that of bulk gold. Additionally, a 15 Hz sinusoidally varying voltage of 15 V peak-to-peak amplitude is applied to the MEMS device to demonstrate that the large membrane deflection is a repeatable deflection (Figure 2).<\/p>\n

These films can be utilized in microspeakers, pressure sensors, microphones, deformable mirrors, tunable optical cavities, and \u00a0large-area arrays of these devices.<\/p>\n\n\t\t