走査型容量顕微鏡による誘電体／伝導性薄膜観察

摘要

Scanning capacitance microscopy (SCM) techniques to investigate the local electronic properties of the ultra-thin films are present­ed. In the first part, we show the application of SCM experiments for the high-permittivity (high-k) dielectric thin films. The static capacitance (dC/dZ) images and spatially resolved dC/dZ versus sample bias spectra have revealed the charge distributions within high-k dielectrics. Moreover, the bias stress examination has clearly imaged the charge-trapped region in the high-k stacked dielec­trics. In the second part, we have demonstrated that the conductance variation ascribed to the graphene thickness can be probed through SCM measurements. The UHF field transmitted from SCM probe tip induces a local accumulation of carriers just beneath the tip. This causes carrier diffusion over the effective biased area of S_(eff) graphene films, which can be detected as the increment of dC/ dZ signal intensity. These results indicate that our SCM technique provides a valuable method to explore the electronic characteristics of low-dimensional materials with nanoscale resolution.%情報処理機器の高速化や低消費電力化は，LSIの基本要素デバイスである金属一酸化膜一半導体電界効果型トランジスタ（MOSFET）の微細化により実現してきた・しかし主要構成材料であるSiやSiO_2の物性的な制約から，これまでのようなMOSFETの等比縮小化，いわゆるスケーリング則はデバイス世代を追う毎にその難易度を高めている．