Static ram having a tft with n-type source and drain regions and a p-type region in contact with only the intrinsic channel of the same

Abstract

To prevent an n-channel thin-film transistor from being deteriorated by hot holes generated in a gate-negative pulse mode. A thin polysilicon filmis provided with a p-type semiconductor regionin contact with a channel region. The p-type semiconductor regionis electrically connected to nowhere except the channel region. Holes induced on the surface due to a gate-negative pulse are further supplied from the p-type semiconductor region. An electric field established by the gate-negative pulse is relaxed by the holes, fewer hot holes are injected into the gate oxide film, and the TFT characteristics are less deteriorated.