Multi-height fin field effect transistors

Abstract

Semiconductor fins are formed on a top surface of a substrate. A dielectric material is deposited on the top surfaces of the semiconductor fins and the substrate by an anisotropic deposition. A dielectric material layer on the top surface of the substrate is patterned so that the remaining portion of the dielectric material layer laterally surrounds each bottom portion of at least one semiconductor fin, while not contacting at least one second semiconductor fin. Dielectric material portions on the top surfaces of the semiconductor fins may be optionally removed. Each first semiconductor fin has a lesser channel height than the at least one second semiconductor fin. The first and second semiconductor fins can be employed to provide fin field effect transistors having different channel heights.