Electrical temperature sensor having one or more layers

Abstract

An electrical temperature sensor has a platinum-containing resistance layer as a measuring resistor, which is applied on the electrically insulating surface of a ceramic substrate. For protection against contamination or damage, the resistance layer is provided on its side facing away from the ceramic substrate with an intermediate layer as a diffusion barrier layer. In a first embodiment, a platinum layer as an electrode is applied on the intermediate layer spaced from the resistance layer. The electrode protects the measuring resistance against platinum poisons, such as stray silicon ions, which could emerge, for example, from a passivation layer made of glass. In a second embodiment, the electrical temperature sensor is provided with a multiple layer, wherein a covering layer is applied on the intermediate layer as a passivation layer made of glass. Also in this embodiment, an electrode in the form of a platinum layer can be applied spaced from the resistance layer. The intermediate layer functioning as a diffusion barrier layer is made of a ceramic containing Al O , MgO or tantalum oxide. Furthermore, it is also possible to insert an intermediate layer made of a layer system with a series of layers of several oxides.