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Study of Direct-Contact HfO2/Si Interfaces
National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8562, Japan
Received: 27 February 2012; in revised form: 5 March 2012 / Accepted: 8 March 2012 / Published: 19 March 2012
Abstract: Controlling monolayer Si oxide at the HfO2/Si interface is a challenging issue in scaling the equivalent oxide thickness of HfO2/Si gate stack structures. A concept that the author proposes to control the Si oxide interface by using ultra-high vacuum electron-beam HfO2 deposition is described in this review paper, which enables the so-called direct-contact HfO2/Si structures to be prepared. The electrical characteristics of the HfO2/Si metal-oxide-semiconductor capacitors are reviewed, which suggest a sufficiently low interface state density for the operation of metal-oxide-semiconductor field-effect-transistors (MOSFETs) but reveal the formation of an unexpected strong interface dipole. Kelvin probe measurements of the HfO2/Si structures provide obvious evidence for the formation of dipoles at the HfO2/Si interfaces. The author proposes that one-monolayer Si-O bonds at the HfO2/Si interface naturally lead to a large potential difference, mainly due to the large dielectric constant of the HfO2. Dipole scattering is demonstrated to not be a major concern in the channel mobility of MOSFETs.
Keywords: MOSFET; high-k; HfO2; interface dipole; channel mobility
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MDPI and ACS Style
Miyata, N. Study of Direct-Contact HfO2/Si Interfaces. Materials 2012, 5, 512-527.
Miyata N. Study of Direct-Contact HfO2/Si Interfaces. Materials. 2012; 5(3):512-527.
Miyata, Noriyuki. 2012. "Study of Direct-Contact HfO2/Si Interfaces." Materials 5, no. 3: 512-527.