This paper presents the geometric effects of a lateral asymmetric channel (LAC) structure for high-voltage (HV) MOSFETs. The LAC structure was adopted to enhance the device performance by modifying the potential distribution in the channel and reducing the parasitic transistor effect. The LAC structure was realized using a p-body doping region inside the channel for the HV device. The effects of the p-body length were examined. The experiments showed that the p-body length is a key parameter for device optimization considering circuit applications. The HV LAC device with a shorter p-body length showed transconductance (g(m)) improvement and on-resistance (R-ON) reduction. The maximized output resistance (r(out)) was obtained when the p-body length was approximately half of the channel length. (C) 2014 Elsevier Ltd. All rights reserved.