Chemical Stability
A hard ceramic material provides a stable resistive layer for use in high-precision electronic circuits and sensor systems. Applying tantalum nitride provides excellent resistance to moisture and chemical corrosion, making it suitable for long-term use in harsh environments. The material is primarily valued for its ability to maintain a constant electrical resistance over a wide range of temperatures.
Phase Stability
Reactive sputtering of tantalum in a nitrogen atmosphere allows for the formation of several different crystalline phases. The hexagonal phase is often preferred for its low temperature coefficient and high stability. Controlling the nitrogen flow during deposition is critical for achieving the desired electrical properties.
Environmental Resistance
The formation of a dense and protective surface oxide prevents further reaction with the atmosphere. This self-passivating nature ensures that the internal part of the film remains unchanged even when exposed to resistance changes caused by humidity, heat, oxidation, or chemical exposure. Because of this stability, the drift in resistance over thousands of hours of operation is remarkably low compared to other thin-film materials.
It is often used as a diffusion barrier between metal layers to prevent the mixing of atoms that would change the device characteristics.
Laser Trimming
Resistors made from this material can be adjusted to very tight tolerances using laser pulses to remove small amounts of material. This process allows for the production of highly matched resistor pairs for differential sensing circuits.
