An integrated circuit includes a gate structure in contact with a portion of semiconductor material between a source region and a drain region. The gate structure includes gate dielectric and a gate electrode. The gate dielectric includes at least two hybrid stacks of dielectric material. Each hybrid stack includes a layer of low-κ dielectric and a layer of high-κ dielectric on the layer of low-κ dielectric, where the layer of high-κ dielectric has a thickness at least two times the thickness of the layer of low-κ dielectric. In some cases, the layer of low-κ dielectric has a thickness no greater than 1.5 nm. The layer of high-κ dielectric may be a composite layer that includes two or more layers of compositionally-distinct materials. The gate structure can be used with any number of transistor configurations but is particularly useful with respect to group III-V transistors.