2001 Fiscal Year Final Research Report Summary
Research of hydrogen reaction dynamics at semiconductor surfaces by multiple-internal-reflection infrared spectroscopy
| Project/Area Number |
11304018
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
NIWANO Michio Tohoku University, Research Institute of Electrical Communication, Professor, 電気通信研究所, 教授 (20134075)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KIMURA Yasuo Tohoku University, Research Institute of Electrical Communication, Research Associate, 電気通信研究所, 助手 (40312673)
|
|---|
| Project Period (FY) |
1999 – 2001
|
| Keywords | Semiconductor / Infrared spectroscopy / Multiple internal reflection / Surface / Adsorption-desorption / Reaction mechanism / Oxidation |
|---|
| Research Abstract |
The aim of this research is to elucidate the behavior of hydrogen atoms at semiconductor surfaces using infrared absorption spectroscopy in the multiple internal reflection geometry. The main conclusions of this research are as follows :
1. The desorption of hydrogen on Si surface is strongly influenced by the microscopic roughness of the surface. We found that the hydrogen desorption at step and defects sites has a lower activation energy than that at dimer sites of the Si(100)(2x1) surface.
2. We confirmed that the water molecules readily adsorbs on the clean Si surface even under ultra-high vacuum conditions. We found that the so-called "C-defects" that have been observed in STM images of the "clean" Si surface, is due to the adsorption of water onto the Si surface. We also proposed a model for the dissociative adsorption of water on Si(100)(2x1).
3. We have investigated the adsorption of SiH_4 on the Si(001)(2x1) surface. Comparing infrared data with the density functional cluster calculation, we showed that at low hydrogen coverage the silane molecule dissociatively adsorbs on Si(001)(2x1) to populate a dihydride (SiH_2) at the bridge site between two adjacent dimers and monohydride species. We suggested that at high hydrogen coverage, silane adsorbs onto a single dimer to generate monohydride and sylil groups (-SiH_3). We also demonstrated that the dihydride species that was initially generated by silane adsorption, decomposes to monohydride species even at room temperature.
4. We have investigated the adsorption of benzene on the Si(001)(2x1) surface. We showed that the adsorption process strongly depends on the surface coverage of benzene : At low coverage, the benzene molecule molecularly adsorbs at the bridge site between two adjacent dimmers, and at high coverage, the molecules preferentially sticks onto a single dimer.
|
