Study on Dynamic Processes of Adsorption and Desorption by means of Time-Resolved Reflectance Spectroscopy
Grant-in-Aid for Scientific Research (C)
|Research Institution||Yokohama National University|
TANAKA Masatoshi Yokohama National University, Faculty of Engineering, Professor, 工学部, 教授 (90130400)
OTA Koyu Yokohama National University, Faculty of Engineering, Research Associate, 工学部, 助手 (90282954)
NAKAJIMA Toshinobu Yokohama National University, Faculty of Engineering, Research Associate, 工学部, 助手 (30017991)
USAMI Seiji Kanagawa Institute of Technology, Professor, 教授 (40017877)
|Project Fiscal Year
1997 – 1998
Completed(Fiscal Year 1998)
|Budget Amount *help
¥3,400,000 (Direct Cost : ¥3,400,000)
Fiscal Year 1998 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1997 : ¥2,500,000 (Direct Cost : ¥2,500,000)
|Keywords||Real-Time measurements / Reflectance Spectroscopy / Multi-Channel measurements / Chemical Adsorption / Silicon / Chlorine / Tungusten / Nitrogen / 実時間測定 / 反射分光 / マルチチャンネル測定 / 化学吸着 / シリコン / 塩素 / タングステン / 窒素 / 酸素|
Dynamic processes of adsorption and desorption of gases on solid state surfaces have been studied by real-time multichannel reflectance spectroscopy, in which adsorption states are specified from spectral structures.
(1) In the case of nitrogen adsorption on W(001) surface, spectral structures at 3.8 and 2.1 eV are found to be correlated with the beta_2 and beta_1 states, respectively. Development of the beta_1 state is firstly obtained by the enhancement of the structure at 2.1eV.Penetration of nitrogens into the bulk is a possible explanation for this state
(2) New findings about chlorine adsorption on Si(111) at room temperature are as follows.
1) Main process is found to be adsorption of atoms without migration. Initial sticking probability to dangling bonds and initial breaking probability of back bonds are determined as 0.48 and 0.14, respectively.
2) The initial breaking probability and the total number of the broken back bonds are larger for heavyly doped silicon. Holes probably weaken the back bonds.
3) A structure originating from optical transitions between the bulk states to the antibonding states of SiCI is found aroud 3.6eV.
(3) A rest-atom surface covered with * SiCI is formed by annealing the chlorine-saturated Si(111) surface at 740K.New findings about chlorine desorption from the rest-atom surface at 880-940K are as follows.
1) Main process is found to be restoration of back bonds. Activation energy is determined as 2.7 eV and this corresponds to the barrier energy for the reaction, SiCl +SiCl *** SiCI_2 + Si.
2) Restoration of dangling bonds are observed only at the initial stage of the desorption.
It has been shown that dynamic processes of adsorption and desorption can be real-time studied by specifying chemical bonds from the structures of reflectance spectra.
Research Output (6results)