FIN-FET ICs with adjustable FIN-FET channel widths are formed from a
semiconductor layer (42). Fins (36) may be etched from the layer (42) and then some (46) locally shortened or the layer (42) may be locally thinned and then fins (46) of different fin heights etched therefrom. Either way provides fins (46) and FIN-FETs (40) with different channel widths W on the same substrate (24). Fin heights (H) are preferably shortened by implanting selected ions (A, B, C, etc.) through a
mask (90, 90′, 94, 94′, 97, 97′) to locally enhance the etch rate of the layer (42) or some of the fins (36). The
implant(s) (A, B, C, etc.) is desirably annealed and then differentially etched. This thins part(s) (42-i) of the layer (42) from which the fins (46) are then etched or shortens some of the fins (46) already etched from the layer (42). For
silicon,
germanium is a suitable
implant ion. Having fins (42) with adjustable fin heights Hi on the same substrate (24) enables such FIN-FET ICs (40) to avoid channel-width quantization effects observed with prior art uniform
fin height FIN-FETs (20).