Fin height and
width can have strong impact on device performance variability. Of the two, fin
height variation is generally more critical 18. Device’s effective electrical
width is directly related to fin height. Hence, any fin height variation due to
variation of fin forming processes directly transfers to device width
variation. Unlike in planar devices, where active area patterning variation
affects only the narrowest of transistors, all fin-based devices suffer from
the same percentage of device width error 18. This variability is primarily
related to definition of fin height by STI dielectric recess process after
polishing planarization and can reach several percent of every device width
18.