Effect of impurity on Si(111)-7*7 self-organization
Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants |
|Research Institution||Waseda University |
OHDOMARI Iwao Waseda Univ.School of Sci.& Engineering・Professor, 理工学部, 教授 (30063720)
|Project Period (FY)
1997 – 1998
Completed (Fiscal Year 1998)
|Budget Amount *help
¥9,400,000 (Direct Cost: ¥9,400,000)
Fiscal Year 1998: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1997: ¥6,800,000 (Direct Cost: ¥6,800,000)
|Keywords||Si(111) 7*7 / Nano-structure / Self organization / Surface modification / STM / In situ observation / Ion irradiation / Oxygen / RHEED / 極高真空 / 構造相転移|
1 Influence of oxygen on the formation of Si(lll)-7*7 domains
The transient aspects of Si(lll)7*7 reconstruction after laser irradiation were observed under the experimental condition of different Si substrate temperature and 0_2 pressure. The 7*7 growth was suppressed easily under higher 0_2 pressure and lower temperature. By means of in situ STM observation of the process, we have found that the preferential oxidation of the unreconstructed disordered region on the surface result in the suppression of the 7*7 growth.
The 7*7 coverage on the quenched surfaces was measured as a formation of cooling speed for the two types of Si wafers with different oxygen concentration with STM.The 7*7 coverage of the sample with higher oxygen concentration was higher than that of the sample with lower oxygen concentration, which suggested that oxygen had an influence on the formation of the 7*7 structure.
A novel inter-atomic potential energy function for Si, 0 mixed systems was developed to realize mol
ecular-dynamics studies on the roles of 0 atoms in the 7*7 reconstruction. By molecular orbital calculations, we clarified that 0 atoms lowered the energetic barrier to form the 7*7 structure.
2 In situ observation of the Si surface modification by ion irradiation using an ion-source /STM combined system
In situ real-time high temperature observation of Si (111) 7*7 surface during ion irradiation in ultra high vacuum was performed for the first time using the ion-source / STM combined system. Sequential STM images of the high temperature surface showed structural change in the surface atomic arrangement before and after ion irradiation.
3 Wafer scale fabrication of nano-structures on Si(lll) surface
Correlation between the surface atomic arrangement and the preferential adsorption site of Cu in a wet-process was investigated. For Cu deposition on hydrogen-terminated Si (111) surface, Cu mano-wires of -50 nm wide were observed in a narrow window of Si potential. We found that Cu nano clusters precipitate at dihydride Si atoms but not at mnonohydride Si atoms. Less
Report (3 results)
Research Products (49 results)