Abstract: In an interstitial concentration simulating method, a mesh is set in a simulation region of a semiconductor device. Under a condition that an area outside of the simulation region is infinite, a provisional interstitial concentration and a provisional interstitial diffusion flux at the boundary of the simulation region are calculated. Then, an interstitial diffusion rate at the boundary of the simulation region is calculated by a ratio of the provisional interstitial diffusion flux to the provisional interstitial concentration. Finally, an interstitial diffusion equation is solved for each element of the mesh using the interstitial diffusion rate at the boundary.

Abstract: An interface unit includes an interface controller for controlling a bidirectional signal relative to an external host computer, a communication controller for controlling data communication with a noncontact IC card according to an output signal sent from the host computer, and a memory accessible by both the interface controller and communication controller. A noncontact IC card is very useful because of its accessibility at a remote place. A connector of the noncontact IC card can be protected from mechanical damage. With the interface unit, the noncontact IC card can be accessed as quickly as a contact IC card is.