P-channel flash with enhanced band-to-band tunneling hot electron injection

A p-channel flash memory is formed with a charge storage stack embedded in a hetero-junction layer in which a raised source/drain is formed. Embodiments include forming a dummy gate stack on a substrate, forming a layer on the substrate by selective epitaxial growth, on each side of the dummy gate stack, forming spacers on the layer, forming raised source/drains, removing the dummy gate stack, forming a cavity between the spacers, and forming a memory gate stack in the cavity. Different embodiments include forming the layer of a narrow bandgap material, a narrow bandgap layer under the spacers and a wide bandgap layer adjacent thereto, or a wide bandgap layer under the spacers, a narrow bandgap layer adjacent thereto, and a wide bandgap layer on the narrow bandgap layer.