Electrically removable, micromachined encapsulation for sensitive materials
Abstract
A new encapsulating technique for sensitive materials in chemical sensors is described. The device functions like a cap which can be mounted on top of the sensitive material and protects it from contact with the surrounding air or fluid. To activate the device, a thin membrane is destroyed by applying a voltage to the membrane heater and thus rupturing the membrane by inducing thermal tensions. Tensile stress causes the membrane to open up completely. The device is fabricated by standard thin-film technology and bulk-micromachining. Two basic kinds of chemical sensor operation can be realized. First its use as a sensor cover to protect the sensor until it is used. This increase the effective lifetime of the sensor and multiplies the system lifetime by the serial use of several encapsulated sensors. Second the devices can be easily combined to an array. This allows the design of a large array with small dimensions of one-shot measurement chemical sensors based on irreversible detection reactions.
