Reliability study on polycrystalline silicon thin film resistors used in LSIs under thermal and electrical stress

A general expression for the sheet resistivity increase of polycrystalline silicon (poly-Si) resistors formed on field oxide under thermal and electrical stress is determined. The increase ratio of the resistivity under thermal stress is proportional to its initial value and square root of aging time with the activation energy of 0.68+or-0.22 eV. The increase ratio of the resistivity under constant DC current is also proportional to the square root of testing time, indicating that this increase is due to the effect of the above-mentioned thermal stress. Carrier trapping center generation is the poly-Si film caused by contact metallization is proposed for this phenomenon.<
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