1. Field of the Invention
The present invention relates to a semiconductor device, particularly to a semiconductor device using an age-based change device (aging device) whose output changes with the elapse of time.
2. Description of the Related Art
As one of the technical problems of a radio frequency identification tag (RFID) called an active chip on which a power supply is mounted, for example, the life of a battery (μ-battery) needs to be lengthened. In addition to lengthening the life of the μ-battery itself, it is also important to save IC power. For IC power saving, miniaturization of the semiconductor device has heretofore been a trend, but in recent years, it has been recognized that the trend has almost reached its limit because of the increase in leakage current due to the miniaturization.
On the other hand, it is assumed that RFIDs are attached to all surrounding matters as utilized, but there is a problem that it is difficult to sort the RFID in disposing the matter to which the RFID is attached. In this case, a material for use in the μ-battery has to be eco-friendly. That is, it is not a situation that any material is usable to achieve long life. Thus, it is very hard to lengthen the life of the μ-battery with ordinary means.
Considered from another application of the μ-battery, it is a problem to reduce cost of the μ-battery itself in a system LSI. That is, the cost cannot be sacrificed in order to maintain the long life while avoiding a material having an environmental load. The lengthening of the life of the battery is also an important problem for an LSI mounted on a car, which continues to operate even while an engine is turned off.
As described above, there has heretofore been a demand for lengthening the life of the μ-battery as one of the technical problems in RFID or the like, but there are problems that the power saving of the IC cannot be expected by the miniaturization of the semiconductor device, a battery having a large environmental load cannot be used, and cost cannot be sacrificed. Therefore, in the present situation, long life cannot be realized yet.
Therefore, there has been a demand for the realization of the semiconductor device capable of substantially extending the life of the μ-battery or the like using the aging device.