Tailored gas-absorbing materials for packaged opto-electronic devices

Recently special gas-adsorbing materials have been developed to capture gaseous contaminants such as moisture, organics and hydrogen in Optical Transceivers, multiplexers, and laser diodes that otherwise may be detrimentally affected by these gases. Hermetically sealed, or semi-hermetic packages are often used to protect High-Reliability Opto-electronic devices from possible damages due to atmospheric gases and harsh environment, aiming for higher performances and longer lifetime of the modules. Nevertheless, sealed devices may experience issues from internal outgassing of gas species like H2O, H-2, and VOCs (Volatile Organic Compounds) released by inner materials or components. As reported in MIL-STD-883, the moisture limit of 5,000 ppm is specified as the critical concentration for which evident corrosion mechanisms are observed in integrated circuits and hybrid components. Moisture can be a problem in several PIC (Photonic Integrated Circuits) devices. It is also known that moisture and hydrogen may have negative effects in High Speed Optical Transceivers or that VOCs may cause problems in Laser Diode modules. Special Getter Materials integrated in the packages - especially in their lids - can successfully fix these issues. New getter materials have been developed to sorb the detrimental gases. In particular they have been designed to cope with MIL requirement for moisture and to ensure very low water concentration, even well below 1,000 ppm. Depending on the device and on the amounts of detrimental gases to be sorbed the getter can be selected and properly sized. It is usually activated by heating in vacuum or nitrogen, immediately before the sealing of the device package