SEMICONDUCTOR DEVICE, ITS MANUFACTURE, AND COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To put up a higher barrier at a low cost to the unauthorized use of a user terminal. SOLUTION: A channel region 2, a source region 3, and a drain region 4 are formed on a polycrystalline semiconductor layer 1. A polycrystalline TFT 101 varies in characteristics depending on the volume of crystal grain boundaries 6 contained in the channel region 2. A drain current becomes smaller with an increase of grain boundaries 6 in the channel region 2. The TFT 101 is mounted together with a coding circuit on a semiconductor chip or a system so as to use codes obtained by coding the electrical properties of the TFT 101 for discriminating a semiconductor chip or a system.