Excellent silicon thickness uniformity on Ultra-Thin SOI for controlling Vt variation of FDSOI

Thickness uniformity of the Ultra Thin SOI (UTSOI) substrates is one of the key criteria to control Vt variation of the planar FDSOI devices. We present an evolutionary approach to SmartCut TM technology which already allows achieving a maximum total SOI layer thickness variation of less than ± 10 A on preproduction volume. Total thickness variation of ± 5 A is targeted.