Thermal analysis of preswitching characteristics of a thin-film amorphous-chalcogenide switch

The preswitching nonohmic behaviour of amorphous-semiconductor switches could result from either Joule heating or space-charge-limited currents. After the `forming¿ of a virgin device, electron-microscope examinations have revealed a channel whose composition differs significantly from the matrix. Also, the I/V characteristics of the blocking states of virgin and formed devices are significantly different. The preswitching I/V characteristics of a Ge15Te81S4 chalcogenide-glass switch at 300 K have been explained by Joule heating in the formed channel, with an estimated temperature rise of 25 degC above ambient at the centre of a monostable switch.