All About Resistors part-3

1.5 Thin film and thick film resistors: 

The principal difference between thin film and thick film resistors is how the film is applied to the cylinder (axial resistors) or the surface (SMD resistors). Thin film resistors are made by sputtering (a method of vacuum deposition) the resistive material onto an insulating substrate whereas thick film are made using screen and stencil printing processes.

 

Ceramic conductors such as tantalum nitride (TaN), ruthenium dioxide (RuO₂), lead oxide (PbO), bismuth ruthenate (Bi₂Ru₂O₇), nickel chromium (NiCr), and bismuth iridate (Bi₂Ir₂O₇) are the materials commonly used for making thin film resistors. Thick film resistors are usually made by mixing ceramics with powdered glass. Thick films have tolerances ranging from 1 to 2% and a temperature coefficient between ±200 or ±250 ppm/K.

 

Thin film resistors are usually more expensive than thick film resistors. Thin film resistors are preferred for microwave passive and active power componentssuch as microwave power resistors, microwave power terminations, microwave resistive power dividers, microwave power attenuators.

 source: engineersgarage.com