Polysilicon air-bridge thermal sensor coupled to log-periodic antenna for infrared detection

An antenna-coupled thermal sensor based on polysilicon was fabricated for mid-infrared radiation detection. The active element made of polysilicon is a thermally isolated air-bridge created by standard micro-machining processes on silicon. The sensor operates at room temperature in both thermocouple and bolometer modes. Preliminary experiments indicate a high electrical responsivity and short time constant. Measurements with a carbon dioxide laser at 10.2 mu m wavelength show the existence of antenna patterns and polarization properties of a log-periodic antenna.