Micro Electro Mechanical System Cryocooler

Development is proposed of a miniature cryogenic refrigerator (microcooler) designec for manufacture using the same micromachining techniques developed for silicon chip electronic, sensor and actuator systems and Iater extended to Micro Electro Mechanical Systems (MEMS). Development of the 'microcooler on a chip' is intended for application to those sensors and electronic systems, semiconductor and superconducting, which require cooling to cryogenic temperatures for their effective or enhanced operation. The cryocooler proposed for development is essentially a Stirling refrigerator with the design adapted to microtechnology manufacturing techniques with silicon as the base material. Compression and expansion of the helium working fluid is effected with thin etched resonant diaphragms acting as a diaphragm compressor and expander. A novel electrical driver for the compressor diaphragm is incorporated. It is anticipated that a distributed cooling system will be feasible for silicon chips with multiple cooled electronic features. The several cooling stations will be mutually coupled to a common compressor module permitting substantial simplification and economies. Development of the cryocooler on a chip will allow for dramatically reduced cost, size and weight of the total sensor and cold electronics package providing enhanced opportunities for greatly extended usage in military, civil, medical, scientific and domestic applications.