Noncontact Atomic Force Microscopy - Yale School of Engineering ...

P.I-27
NC-AFM study of a cleaved InAs (110) surface using modified Si probes
under ambient atmospheric pressure
Yonkil Jeong 1,2 , Masato Hirade 2,3 , Ryohei Kokawa 2,3 , Hirofumi Yamada 2,4 ,
Kei Kobayashi 2,4 , Noriaki Oyabu 2,4 , Hiroshi Yamatani 2,5 , Toyoko Arai 2,5 ,
Akira Sasahara 1,2 , and Masahiko Tomitori 1,2,*
1 School of Materials Science, Japan Advanced Institute of Science and Technology, Ishikawa, Japan,
2 JST Advanced Measurement and Analysis, 3 Shimadzu Corp., Kyoto, Japan,
4 Kyoto University, Kyoto, Japan, 5 Kanazawa University, Ishikawa, Japan
Characterization of crystalline defects in thin films with interfaces of lattice-mismatched
III-V compound semiconductors such as GaAs and InP is an important issue for practical
device application. We pursue a simple and quick method to characterize them on an
atomic scale using NC-AFM by cleaving devices in a controlled environment without a
UHV system. In this work, we demonstrate the possibilities of high-resolution imaging of
a cleaved InAs (110) surface using the NC-AFM under atmospheric pressure of air or
pure Ar, and of acquiring charge state information with specially fabricated probes,
which are designed to emphasize electronic interaction between the tip and the sample.
High aspect ratio (HAR) Si and Ge/Si probes were fabricated from commercial
AFM Si probes by an FIB and a Ge deposition system. Fig. 1(a) shows the changes in ? f
due to the reduction of capacitance between probes and a sample. A high resolution
image with a periodic structure was successfully obtained with a fabricated probe, in Fig.
1(c); possibly residual H2O molecules were adsorbed on a cleaved InAs (110) surface.
(a (b
Δf = -43Hz, A = 0.4nm
Figure 1: (a) Bias-Δf curves between probes and a sample surface. (b) SEM images of
FIB fabricated probes. (c) NC-AFM image of a cleaved InAs (110) with HAR-Si in Ar.
*corresponding author e-mail: tomitori@jaist.ac.jp
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(c)