Graded AlN/Al2O3 Precursor and Methods to Passivate Micro-Channel Coolers

Commercially available micro-channel coolers for high power laser diodes utilize copper's high thermal conductivity and ability to be micro-machined. Unfortunately, these coolers suffer from flow erosion and corrosion by the cooling fluid. Copper's ability to conduct electrical charge furthers the corrosion process and requires the use of deionized water as the heat carrying fluid. These factors increase operation costs and can lead to failure of the laser. Eltron Research & Development Inc. proposes the use of a proprietary precursor and deposition method to coat the micro-channel coolers with a graded AlN/Al2O3 layer. This hard, chemically resistant layer maintains high thermal conductivity while providing an electrical insulating barrier to protect the copper core from corrosion. The coating will extend the life span of the unit as well as allow for the use of filtered tap water for the cooling fluid. This will lower the cost of the high power laser diode unit over its life span and help prevent laser failure caused by flow erosion and corrosion.