Abstract
Free-standing tungsten filament and vacuum seal with glass cover to work as a miniature planar incandescent light source are studied. Different to the LED and semiconductor laser, the micro-lamp emits boardband visible light, and is useful for calibration source for micro-spectrometers and display source. The planar structure is easy to integrate with silicon-based Micro Optical Electromechanical System (MOEMS) device and driving circuits. Low stress tungsten deposition parameters are optimized, and remains flat when suspended over cavity etched into silicon. Deep glass etching in hydrofluoric is studied to realize the microcavity and electrical feedthrough. The lateral etching rate is about twice of vertical etching, and shows “anisotopic” etching characteristic. The fabricated micro-lamp was measured in the pumped vacuum chamber, and the high temperature melting point of tungsten emits intense white light when self heated up to high temperature by voltage supply. The filament is 5000μm x 12μm x 0.5μm and the light emitting threshold electrical driving power is 8 mW.