Electrical estimation of channel dopant uniformity using test MOSFET array

The dopant uniformity in an MOSFET channel is estimated using the test MOSFET array which includes many MOSFETs with different channel length. Takeuchi coefficient as a function of the channel length is calculated from the measured threshold voltage data. The electrical channel length as a function of the gate voltage is extracted using channel resistance method. It is found that those data show the similar degree of the dopant uniformity for MOSFETs having various channel structures.