Influence of initial surface reconstruction on the interface structure of HfO2/GaAs

✍ Scribed by Tetsuji Yasuda; Noriyuki Miyata; Akihiro Ohtake

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 431 KB
• Volume: 254
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2008.01.032

✦ Synopsis

We show that the bonding structures and electrical properties of the HfO 2 /GaAs interface can be controlled by a choice of the reconstruction on the initial GaAs surface. Electron-beam evaporation of HfO 2 onto the c(4 Â 4) surface yielded As-O bonds at the interface, while Ga-O bonds were dominant at the interfaces formed on the (2 Â 4) and (4 Â 6) surfaces. Influences of the initial surface reconstruction on the interface structure persisted even after annealing at 673 K. Electrical characterization of Ir/HfO 2 /GaAs capacitors indicated that the interfacial As-O bonds cause weak Fermi level pinning. It was also suggested that the interfaces dominated by the Ga-O bonds have trapping states in the upper half of the GaAs bandgap.