Schottky base edge leakage in Si permeable-base transistors

The base leakage/breakdown mechanism in the Si permeable-base transistor (SiPBT) is related to the radius of curvature of the depletion region directly below the edge of the metal semiconductor interface. The unique geometry of the SiPBT illustrates the edge breakdown phenomena. As higher reverse bias is applied to the base-collector junction, the adjacent depletion regions in the grating fuse and the exposed edge perimeter will vary to form a kink in the IV characteristics. The grating will self-guard. As the SiPBT design parameters are scaled to finer gratings, the carrier concentration under the base must increase to maintain permeable-base transistor action. These fine-period SiPBT´s will also self-guard within the grating region.