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 optimized to minimize the deviation of the U/I characteristic from the ideal curve.
This approach makes a cost-saving and reliable single-point calibration possible for the first time.
The use of SOI technology and the resulting reduction in leakage currents has made it possible to achieve a high degree of measurement stability in a temperature range of up to 220°C.
Project presentation at:
COMPAMED, November 16-19, 2015, Düsseldorf, Hall 8a, Booth H23.1
Characteristic curves of 12 different diodes from one production