The JonDeTech Difference
The thermopile leads can be arranged in different manners; for most commercial sensors of today, typically, horizontal or “in-the-plane” architecture is used. The reason for this is strictly process related. Microelectronic processes have historically been developed to make lateral structures on silicon wafers. However, this is not always the best sensor solution since the hot and the cold junctions are placed next to each other on the same surface. To use this as a infrared sensor an aperture must be integrated with the thermopile so that the heat radiation strikes only a limited area, i.e. the hot junction of the sensor. In other words, the full surface of horizontally configured thermopiles
can’t be used, neither can true “contact mode” be utilized.
The advantage of the vertical thermocouple lead arrangement (perpendicular to plane configuration) is that the hot and cold junctions are separated by the thickness of the substrate–the heat gradient is through the substrate. The object measured can be close to the sensor or actually come in contact with the sensor.
Vertical or “out-of-the-plane” configuration requires that the leads of the thermocouples are created through the substrate material, i.e. “via” interconnections are required. These vias have to be very small, which has been difficult to achieve previously. However, thanks to creative
thinking and research at Uppsala University, an innovative idea with thermocouple lead-
structures based on nanotechnology has been realized, which is what JonDeTech Sensors AB offers.
Read more about the History of Thermopiles.