1996 Fiscal Year Final Research Report Summary
In situ SEM study of 2D to 3D transition process of strained MBE
| Project/Area Number |
08455015
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied materials science/Crystal engineering
|
|---|
| Research Institution | Osaka Prefecture University |
|---|
Principal Investigator |
INOUE Naohisa Osaka Prefecture University Professor, 先端科学研究所, 教授 (60275287)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HONMA Yoshikazu NTT Basic Research Laboratories, 材料物性基礎研究所, 特別研究員
HUJIMURA Norihumi Osaka Prefecture University Asso. Prof., 工学部, 助教授 (50199361)
|
|---|
| Project Period (FY) |
1996 – 1998
|
| Keywords | compound semiconductor / strained layer / molecular beam epitaxy / three dimensional growth / in-situ observation / scanning electron microscope / Monte Carlo simulation / self organization |
|---|
| Research Abstract |
1. In-situ SEM observation
(1) Lattice matched system : Two demensional-to three dimensional growth transient processes of lattice matched GaAs on GaAs molecular beam epitaxy (MBE) are observed by in-situ scanning electron microscopy (SEM). Phase diagram of 2D-3D growth regime is obtained. Three types of transition are found and island-on-island formation is found to be the principal elementary process. Preferential formation of 3D isiands is observed at the step edge under some growth conditions.
(2) Lattice mismatched system : Preferential formation of 3D islands is observed at the bunched steps in GaAs on Si strained system and the mechanism is discussed.
(3) Work function measurement : In-situ and nondestructive measurement of local work function which is important for nano-structure fabrication is developed.
2. Atomic force microscopy (AFM)
AFM observation is performed on GaAs on (111) surface which is important for self-organized quantum dot formation. SEM image and AFM image are compared for Si (111) surface and the difference between the clean and processed surfaces is revealed.
3. Three dimensional growth model
A model is proposed for the formation of 3D islands where unti-phase domain foundaries between the adjucent reconstructed surface structure serve as island nucleation sites.
4. Theoretical analysis and computer simulation
Compositional ordering due to 3D island formation in SiGe on Si strained system is studied by X-ray diffracion and computer simulation. It is revealed that interdiffusion between the film and substrate and suifiace reconstruction play important roles. SEM contrast formation is simulated by considering the individual electron scattering processes and the asymmetric step contrast due to the relative arrangement of step and detector is obtained.
5. Island control
Based on the above results, control methods of 3D island density and location are proposed. GaAs islands are successfully arrayed by forming step networks on Si (111) surface.
|
