Abstract

The study of small semiconductor devices has made large contribution to solving the low-frequency 1/f noise problem. Experiments (see review [1]) have shown that the less size of device, the easier to observe that the 1/f current noise consists of the unit acts, which are often called random telegraph signals (RTSs) because of their shape. An RTS represents the jumps of a currents between two fixed levels, the duration of the jumps is instantaneous in practice in comparison to the duration of both states of the current, so the RTS is seen as sequence of the current up and down steps of the same value between high and low current states. The times between two neighboring steps are distributed at random with the mean times of high and low current states being very long. The less the size of the device, the less the number of RTSs observed simultaneously and the higher the relative contribution of each RTS to the total current. In submicron devices under certain conditions it is possible to study a single RTS [2]. RTS is caused by capture and emission of electrons (or holes) by a slow electron trap. Thus the study of an RTS in a small-size device permits to investigate the properties of a single slow trap existing in it. The effect of the external parameters, such as temperature, voltage etc. on RTS is generally much more pronounced than that of the 1/f noise consisting of many RTSs. This is the reason why the study of RTSs in submicron devices has given a new valuable information.

© 1997 Optical Society of America