Semiconductor device having increased elctrostatic breakdown voltage.

摘要

A semiconductor substrate (10) has a plurality of MOS transistors (11, 12) formed therein. Each of the transistors comprises high density diffusion regions (N<+>) having high impurity density and serving as source and drain, low density diffusion regions (LDDN-) having low impurity density and extending in contact with the high density diffusion regions, respectively, a channel region (CH) formed between the low density diffusion regions, and a gate (G) formed above the substrate and insulated from the channel region. One (11) of the transistors has its drain connected to an input/output terminal . The low density diffusion region of the one (11) has impurity density higher than that of the other (12). The channel length of the one (11) is greater than that of the other (12). <IMAGE>