Robust semiconductor-on-ferroelectric structures with hafnia–zirconia–alumina UTBOX stacks compatible with CMOS technology

Abstract

Silicon wafers with an ultrathin buried high-k oxide were fabricated by the atomic layer deposition of high-k layers on sapphire and silicon substrates with subsequent silicon layer transfer onto their surfaces by bonding and rapid thermal annealing (RTA). An extremely high thermal stability of hafnia orthorhombic Pca21 ferroelectric phase of up to 1100 °C was observed in the silicon-on-ferroelectric structure on the sapphire substrate. Silicon–ferroelectric–silicon structures with hafnia BOX and alumina inclusions also demonstrated increased thermal stability for hafnia or hafnia–zirconia alloys during the RTA treatment up to 900 °C, which makes them fully compatible with current complementary metal oxide semiconductor technology, promising integrated circuits for neuromorphic computation and optoelectronic switching devices.