A Stability Study of Laser-Patterned Thermally Stabilized Tantalum Nitride and Tantalum Aluminum Films

Tantalum nitride and tantalum aluminum thin-film power resistors were reactively sputtered on 99+ percent alumina ceramic substrates in an argon atmosphere, thermally stabilized, and laser patterned into serpentine paths (two to ten meanders) to obtain final values two to two hundred times their initial values. The resistors were then subjected to many tests to determine their stability. Data from the load life test, after 5000 h at 13.3 W/in2 in a 66°C ambient, indicate that thermally stabilized tantalum nitride and tantalure aluminum resistors may be laser patterned without affecting the films´ intrinsic stability, provided certain constraints in the resistors´ geometry are recognized and observed by the designer.