CD74HCT4067: i/o structure

Qing,

Why do you need to know the internal structure of the signal switch?  Your pictures were low resolution and I could not make them out but I can tell you that the CD74HCTXXXX family of devices have transmission gate on the I/O path an NMOS FET in parallel with PMOS.  This is as much information I can provide about the device that is not proprietary. 

Thank you,

Adam