Temperature diodes on Si-wafer
Semiconductor diodes and transistors are small, inexpensive, highly sensitive and almost linear temperature sensors. Due to the manufacturing process, there is always a scattering of specimens, which prevents interchangeability without individual calibration.
At the CiS Research Institute, technological processes for silicon wafers (Fig. 1) were developed with which a reproducible sensitivity dU/dT, i.e. the slope of the voltage versus temperature, could be achieved (Fig. 2).
Through process simulations and subsequent test series, both the implantation parameters and the geometry factors were optimised to minimise the deviation of the U/I characteristic from the ideal curve. With this approach, a cost-saving and reliable single-point calibration is possible for the first time.
By using SOI technology and the resulting reduction of leakage currents, it has been possible to achieve a high stability of the measurement in a temperature range of up to 220 °C.
Project presentation at:
Hannover Messe, 25-29 April 2016, Hannover, Hall 4 Stand F34
SENSOR+TEST, 10-12 May 2016, Nuremberg, Hall 5 Stand 5-364
Kennlinien von 12 verschiedenen Dioden aus einer Fertigung