title: Al2O3Passivation Effect in HfO2·Al2O3Laminate Structures Grown on InP Substrates.
abstract: The passivation effect of an Al2O3layer on the electrical properties was investigated in HfO2-Al2O3laminate structures grown on indium phosphide (InP) substrate by atomic-layer deposition. The chemical state obtained using high-resolution X-ray photoelectron spectroscopy showed that interfacial reactions were dependent on the presence of the Al2O3passivation layer and its sequence in the HfO2-Al2O3laminate structures. Because of the interfacial reaction, the Al2O3/HfO2/Al2O3structure showed the best electrical characteristics. The top Al2O3layer suppressed the interdiffusion of oxidizing species into the HfO2films, whereas the bottom Al2O3layer blocked the outdiffusion of In and P atoms. As a result, the formation of In-O bonds was more effectively suppressed in the Al2O3/HfO2/Al2O3/InP structure than that in the HfO2-on-InP system. Moreover, conductance data revealed that the Al2O3layer on InP reduces the midgap traps to 2.6 × 1012eV-1cm-2(compared to that of HfO2/InP, that is, 5.4 × 1012eV-1cm-2). The suppression of gap states caused by the outdiffusion of In atoms significantly controls the degradation of capacitors caused by leakage current through the stacked oxide layers.
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.|Center of Opto-Electronic Materials, Korea Institute of Science and Technology , Seoul 136-791, Korea.
authors.forename: Hang-Kyu
authors.initials: HK
authors.lastname: Kang
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Yu-Seon
authors.initials: YS
authors.lastname: Kang
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Dae-Kyoung
authors.initials: DK
authors.lastname: Kim
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Min
authors.initials: M
authors.lastname: Baik
authors.affiliation: Center of Opto-Electronic Materials, Korea Institute of Science and Technology , Seoul 136-791, Korea.
authors.forename: Jin-Dong
authors.initials: JD
authors.lastname: Song
authors.affiliation: Department of Material Science and Engineering, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Youngseo
authors.initials: Y
authors.lastname: An
authors.affiliation: Department of Material Science and Engineering, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Hyoungsub
authors.identifier: http://orcid.org/0000-0001-6518-3563
authors.initials: H
authors.lastname: Kim
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Mann-Ho
authors.identifier: http://orcid.org/0000-0002-5621-3676
authors.initials: MH
authors.lastname: Cho
keywords: Al2O3 passivation layer; HfO2 laminate structure; defect states; indium phosphide; interfacial reaction