Gate capacitance characteristics of gate N/sup -/ overlap LDD transistor with high performance and high reliability

The authors present the gate capacitance characteristics of the gate/N/sup -/ overlap LDD (lightly doped drain) transistor. The gate capacitance was directly measured by a four-terminal method, using an LCR meter. The measured results for the overlap LDD were compared with those for the single drain and the LDD structure. It was demonstrated that the gate/drain capacitance for the overlap LDD is smaller than that for the single drain and as small as that for the LDD in spite of the large overlap length between the gate and the N/sup -/ region. This result was also confirmed by simulation, which indicates that the small gate/drain capacitance of the overlap LDD is due to the depletion of the N/sup -/ drain under the gate by the normal electric field from the gate and the lateral electric field at the drain.<
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