Accurate control of distance between suspended semiconductor nanowires and substrate surface

Abstract

A method of forming a semiconductor device is provided. The method includes providing a structure including, a handle substrate, a buried boron nitride layer located above an uppermost surface of the handle substrate, a buried oxide layer located on an uppermost surface of the buried boron nitride layer, and a top semiconductor layer located on an uppermost surface of the buried oxide layer. Next, a first semiconductor pad, a second semiconductor pad and a plurality of semiconductor nanowires connecting the first semiconductor pad and the second semiconductor pad in a ladder-like configuration are patterned into the top semiconductor layer. The semiconductor nanowires are suspended by removing a portion of the buried oxide layer from beneath each semiconductor nanowire, wherein a portion of the uppermost surface of the buried boron nitride layer is exposed. Next, a gate all-around field effect transistor is formed.