Importance of interface engineering for synthesis of SrHfO_3 perovskite thin films on Si substrates through crystallization of amorphous films and control of flat-band voltages of metal-oxide-semiconductor capacitors

摘要

We studied the crystallization behavior of perovskite SrHfO_3 films on Si substrates, which are a candidate for a new gate dielectric film of MOSFETs. It is found that the diffusion of Sr atoms into the Si substrate changes the chemical composition of the film and disturbs the formation of perovskite-type crystals. To overcome this situation, SiN film is demonstrated to be an effective barrier layer. Perovskite-type SrHfO_3 crystals are obtained by annealing at higher than 800 ℃. The interfacial silicate layer induces a negative flat-band voltage (V_(FB)) shift in MOS capacitors. The importance of a terminating layer for the control of V_(FB) is discussed by comparing with epitaxial perovskite-type crystals.