Reactively sputtered tantalum thin film resistors Part 2. Low energy, low fluence proton radiation damage

Abstract

Tantalum thin film resistors which were reactively sputtered in oxygen and nitrogen simultaneously were bombarded with 150 keV protons to obtain the conductance-fluence characteristics. The conductance of heat treated films increased as a linear function of fluence at room temperature, for values of fluence up to the measured value of 10 16 p/cm 2. This linear conductance increase may be accounted for by radiation-produced defect levels within the intergranular crystalline oxide regions of the discontinuous films. The rate of conductance change with fluence was a maximum for a total reactive partial pressure in the range of 2 × 10 -5 torr, falling off for both greater and smaller total reactive partial pressures. For non heat treated films, the conductance increased as a non-linear function of fluence. This non-linear increase may be accounted for by defect trapping within the amorphous inter-granular oxide. The damage rate as a function of proton beam energy followed the Rutherford law over the range of 50 keV to 150 keV.