Physical Structure 1 。 Source and Drain terminals are identical except that Source provides charge carriers,and Drain receives them. MOS devices have in fact 4 terminals: Source,Drain,Gate,Substrate (bulk) Q Metal D Source (S) Gate (G) Drain (D) 0 0 Q Oxide (SiO2) Metal Oxide (SiO2) (thickness fax) Source region Channel n n region -L p-type substrate p-type substrate (Body) (Body) Channel region B Body Drain region (B) (a) (b) Microelectronic Circuits,2004 Oxford University Press 心2西/2020/3/7 4 SM 13 EECE 488 ± Set 1: Introduction and Background Physical Structure - 1 ‡ Source and Drain terminals are identical except that Source provides charge carriers, and Drain receives them. ‡ MOS devices have in fact 4 terminals: ± Source, Drain, Gate, Substrate (bulk) © Microelectronic Circuits, 2004 Oxford University Press