Stability of Mo Gate MOS Devices Using High Purity Sputtering Target

A Mo (molybdenum) sputtering target with a purity of five nines (99.999%) is developed. The stability of Mo gate MOS devices fabricated using this high purity target is also examined. No mobile charges are observed even in MOS capacitors annealed at 1000°C in nitrogen. The breakdown strength of MOS capacitors with a very thin gate oxide 60 Å thick is held at 12 MV/cm after 1000°C annealing. Long-term stability is also improved using this high purity Mo target.