Aluminum nitride is characterized by a very high thermal conductivity in the range of 180 W/mK to 200 W/mK, good dielectric properties and a coefficient of thermal expansion which is near to that of silicon. These properties make aluminum nitride an attractive substrate material for power electronics and microelectronics. For thick-film compatible paste systems, low-melting glasses free of heavy metal oxides with an adjusted CTE are required as they do show negligible reactivity against nitride ceramics. Glasses are used to promote adhesion as well as to cover and insulate metallizations. Glasses are developed in close collaboration with the “Thick-film technology and photovoltaics” group.