Electronic device having plural fin-fets with different fin heights and planar fets on the same substrate

Abstract

Electronic devices (') of superior design flexibility that avoid channel-width quantization effects common with prior art fin-type (FIN) field effect transistors (FIN-FETS) () are obtained by providing multiple FIN-FETs () and at least one planar FET (′) on a common substrate (), wherein the multiple FIN-FETs () have fins () of at least fin heights Hand H, with H<H. The multiple FIN-FETs () and the at least one planar FET (′) are separated vertically as well as laterally, which aids electrical isolation therebetween. Such electrical isolation can be enhanced by forming the planar FET () in a semiconductor region () insulated from the common substrate (). In a preferred embodiment, the multiple height fins () are obtained by first forming all fins (′) of common height Hand then shortening some of the fins () to height H<Hby differentially etching upper portions thereof that have, preferably, been implanted with etch rate altering ions.