Associate Professor, Research Center for Quantum Effect Electronics, Tokyo Institute of Technology
Nanofabrication process for semiconductors using atomic force microscope
Scanning probe microscopes (SPMs), such as scanning tunneling microscopes (STMs) and atomic force microscopes (AFMs), are now routinely used as tools not only for observing surfaces but also fabricating nanoscale structures. Currently, technology using SPMs is attracting considerable attention as a new nanolithography method.
In the work, an AFM tip-induced direct nano-oxidation method has been developed to fabricate nanoscale p-GaAs oxide dots and wires. The remarkable point of this study is that the heavily carbon-doped GaAs, which shows semi-metal conduction, was oxidized using this method. Furthermore, the oxidized material is easily etched by water. Therefore, by adjusting both oxidation and etching process conditions, a groove with 40nm width and 6nm depth was successfully fabricated.
GaAs is a well-known material for the fabrication of semiconductor heterostructures, and InAs quantum dots are easily grown on the GaAs substrate. Therefore, this AFM-based oxidation process is directly applicable to the development of nanoscaled semiconductor devices. We are now trying to achieve the positioning of InAs quantum dots by using AFM-oxidized patterned GaAs substrates.
 |
| Fig. 1 Large Image |
|---|
| AFM surface images are shown in the figure. The image after fabrication of oxidized material is shown on the left-hand side and the image after etching is shown on the right-hand side. The width of groove is about 40nm. |
 |
| Fig. 2 Large Image |
|---|
| An AFM image of a semiconductor / insulator / semiconductor structure is shown in the figure. The channel material was heavily carbon-doped GaAs and the oxide barrier with a width of 40nm was fabricated using the AFM-based oxidation process. |
Relevant papers
- Matsuzaki, Y., Yamada, A. & Konagai, M.
Nanofabrication of heavily carbon doped p-type GaAs by atomic force microscope nano-oxidation process and its application to single hole transistors.
2002 International Conference on Molecular Beam Epitaxy (2002). - Matsuzaki, Y., Hasui, S., Kamada, S., Yamada, A. & Konagai, M.
Improvement in Aspect Ratio of p-GaAs Oxide Fabricated by Atomic Force Microscope (AFM)-Based Nanolithography Using Pulsed Voltage.
Jpn. J. Appl. Phys. 40[6B], 4325 (2001). - Matsuzaki, Y., Yamada, A. & Konagai, M.
Improvement of Nanoscale Patterning of Heavily Doped p-type GaAs by AFM-Based Surface Oxidation Process.
J. Cryst. Growth, 209, 509 (2000).
