In this work, we report the development of high-resolution real-time infrared microscopy and performance characteristics of single-layer self-supported polycrystalline silicon germanium micro-emitter arrays fabricated using a surface micromachining technique performed at IMEC CMOS sub-micrometer line1. The thermal micro-emitters with 60 micrometer-pixel pitch have been composed into 200 × 1 linear arrays and 14 × 14 two-dimensional ones. The characterization has confirmed a unique uniformity of both, a resistance and thermal coefficient of resistance, i.e. less than 1%, which is the advantage of SiGe technology and 0.5 micrometer design rules. To enhance stiffness and prevent bending problems, the micro-emitters were featured with a pattern of U-shape profiles on both, the supporting legs and the pixel itself each 0.2 micrometer-thin pixel and supporting legs. The resonant cavity was tuned at a 9.6 micrometer wavelength. Although the pixel geometry, its supporting legs and SiGe doping levels have not been optimised to the moment, the single-pixel apparent temperatures exceeding 600 K in CW mode were registered when tested with IR microscope in 8 – 12 micrometer spectral range at room temperature. Also reported are 2-dimentional light distribution across single pixels, a rise-fall time (i.e., a time constants), the pixel-to-pixel cross-talk and the nonuniformity of light emitted by array pixels. A feasibility of 2-dimensional SiGe arrays is discussed. The related research on decrease of the process temperatures is currently ongoing to ensure CMOS-compatibility of SiGe micro-emitters with the underlying switches and multiplexers.
© 2004 Optical Society of AmericaPDF Article