Charge injection transistor using high-k dielectric barrier layer

Abstract

The present invention relates to a heterojunction structure based upon the oxide/high-k dielectric barrier. In exemplary embodiment, a silicon layer has a silicon dioxide layer thereon, and a high-k dielectric material disposed on the oxide layer. Thereafter, a metal layer, serving as the gate metal for the device is disposed on the high-k dielectric. The silicon dioxide layer has a relatively high barrier height, but has a relatively small thickness, and relative to the high-k dielectric, the barrier height differential fosters real space transfer. In this structure, the high barrier height of the silicon dioxide layer results in higher mobility and thereby greater substrate current. By virtue of the relative thick layer of high-k dielectric, leakage current is significantly reduced. Thus, the high-k dielectric material/oxide interface gives the needed barrier thickness to prevent leakage, but enables tunneling of hot electrons through the silicon dioxide into the metal layer with a sufficient applied voltage.