Improved Body Effect and Analog Characteristics of n-Channel MOSFET With Lateral Asymmetric Substrate Doping

An n-channel MOSFET with lateral asymmetric substrate doping (LASD) is presented in this paper. The proposed LASD device has a p-well on the source side and a p-substrate on the drain side. The LASD MOSFET was designed by the simple p-well layout approach and fabricated using the 0.18 μm standard low-voltage CMOS process without any process modification. The experimental measurements showed the improved analog performances of the LASD MOSFET: higher transconductance (gm), lower drain conductance (gds), lower drain induced barrier lowering, higher transconductance generation factor (gm/I_D), and higher Early voltage (V_EA). In addition, the LASD device showed strong body-effect immunity: smaller V_T shift according to body bias and lower body bias sensitivity factor (gmb/gm).