A PtNiGe resistance thermometer for cryogenic applications

Resistance thermometry is a widely employed technique for general-purpose temperature measurements, with applications ranging from basic thermal physics experiments to industrial use in the automotive, aerospace, and microelectronics industries. Platinum is one of the most commonly used materials for resistance thermometry in microfabricated devices due to its broad range of temperature coverage, ease of fabrication, and compatibility with numerous microfabrication processes. For cryogenic applications below 10 K, transition metal oxynitrides and negative temperature coefficient alloys are the dominant choice owing to their superior temperature sensitivity in this range compared to pure metallic thin films. However, these materials often require arduous process development to optimize their sensitivity and may be constrained by a diminutive thermal budget. In this paper, we present a PtNiGe thermometer that has both the fabrication simplicity and thermal stability traits of a Pt thin film. We characterize this PtNiGe material system for a series of annealing temperatures and analyze its sensitivity and temperature coefficient of resistance. We find that this thermometer maintains a performance similar to Pt thin films at 40 K with a sensitivity just one order of magnitude below that of a high performance, commercial thermometer at 380 mK. This PtNiGe thermometer represents a middle ground between Pt thin films and commercial devices.