THERMAL-STRESS EFFECTS ON CAPACITANCE AND CURRENT CHARACTERISTICS OF CU SI AND CU/TIN/SI SCHOTTKY-DIODES/

Schottky diodes are discussed as an alternative for pn junctions for a pplication to Cu diffusion barrier tests. The Cu/TiN/p-Si system seems very promising for sensitive leakage current tests since Cu is shown to have a significantly lower barrier height to p-Si (0.55 + 0.01 eV a s deposited) than TiN (0.90 +/- 0.01 eV after 300 degrees C, 60 min). Furthermore the TiN/p-Si diodes maintain a high Schottky barrier even after annealing at 700 degrees C (0.8 +/- 0.01 eV). An application of the proposed barrier test is given by an investigation of the thicknes s and N-2 flow dependence of reactively sputtered TiN diffusion barrie r stability. While most samples show increased leakage currents after 450 degrees C, the one with the 20 nm TiN barrier maintains its low le akage current up to 500 degrees C annealing.