Thin film resistors primarily utilize tantalum nitride (Tan) or nichrome as the resistive material.
Thin film resistors are a type of resistor that utilizes a thin layer (film) of resistive material deposited onto a ceramic base or substrate. This thin film is typically applied using vacuum deposition techniques such as sputtering or evaporation. The choice of material is crucial for determining the resistor's electrical properties, including resistance value, stability, and temperature coefficient.
Based on common manufacturing practices and as noted in relevant resources, the materials most often employed for creating this resistive layer are:
- Tantalum Nitride (Tan): Known for its stability and relatively low temperature coefficient of resistance (TCR).
- Nichrome: An alloy of nickel and chromium, widely used due to its high resistivity and good stability over a range of temperatures.
These materials are selected because they can be deposited precisely in very thin layers and exhibit stable resistive properties.
Sheet Resistance Range
One characteristic defined by the material and its thickness is the sheet resistance, measured in ohms per square (Ω/sq). For thin film resistors, the achievable range of sheet resistance is typically limited. As indicated, a common range is from perhaps 5 ohms/square to 250 ohms per square.
This range is suitable for many applications, but it is less broad compared to other resistor technologies like thick film technology, which provides a far greater range of possible sheet resistance values. This difference in range influences which technology is chosen for specific electronic circuit designs requiring very high or very low resistance values that fall outside the typical thin film range.
In summary, while other materials might exist for specialized applications, the most common and widely used materials for the resistive element in thin film resistors are tantalum nitride and nichrome.
