Accurate characterization of gate-N/sup -/ overlapped LDD with the new L/sub eff/ extraction method

Accurate characterization of the gate-N/sup -/ overlapped LDD (lightly doped drain) is carried out, based on the newly extracted L/sub eff/ which corresponds to the metallurgical channel length. Current drive improvement of the overlapped LDD over the conventional LDD is not so large as expected when the comparison is based on the same metallurgical channel length. Gate-source/drain overlap capacitance calculated from the newly extracted overlap length is useful for accurate analysis of propagation delay. It is shown that the current drive improvement of the overlapped LDD does not overcome the increase of the overlap capacitance and that the propagation delay of the inverter with overlapped LDD is larger than that of the conventional LDD, when these two LDDs are optimized for hot carrier reliability.<>