Elementary Processes of Surface Photodissociation by Time-Resolved Photoelectron Spectroscopic and Laser Spectroscopic Techniques

本文用激光技术和光电子能谱技术研究了卤素和有机金属化合物在绝缘体、金属和半导体上的热解和光解，在100 K下，用193或351 nm的激光照射Si片上的多层Cl_3或CH_3Cl，既导致这些分子的光解，又形成光刻产物。测量了光碎片（Cl，CH_3）和刻蚀产物（SiCl，SiCl_2）的动能分布，用X射线光电子能谱研究了三甲基镓（TMGa）和三甲基铟（TMIn）在Si，Au和Al衬底上的热解。结果表明，Si（111）衬底上的TMGa和TMIn在200 K时解离为Ga、In和CH_3，而CH_3在更高温度时解离为C、CH和CH_2。在193和226 nm的入射波长下观察到TMGa和TMIn在Si、GaAs或Au上的单层的光解离;在该波长下发生被吸收分子的直接吸收。用飞行时间质谱研究了100 K时吸附在石英衬底上的四甲基锡、三甲基镓、三甲基铟和二甲基锌等有机金属化合物的光解离动力学，主要检测到CH_3光碎片。

We have studied pyrolytic and photolytic dissociation of halogen and organometallic compounds on insulators, metals, and semiconductors with laser techniques and photoelectron spectroscopic techniques.Laser irradiation at 193 or 351 nm of a multilayer of Cl_3 of CH_3Cl on an Si wafer at 100 K leads to both photodissociation of these molecules and formation of photoetchig products. The kinetic energy distributions of photofragments (Cl, CH_3) and etching products (SiCl, SiCl_2) were measured.Pyrolytic dissociation of trimethylgallium (TMGa) and trimethylindium (TMIn) on Si, Au, and Al substrates was studied at various temperatures from 80 to 670 K by x-ray photoelectron spectroscopy. The results indicate that TMGa and TMIn on Si (111) dissociates into Ga, In, and CH_3 on the substrateeven at 200 K and CH_3 surther dissociates into C, CH, and CH_2 at higher temperatures. Photodissociation of a monolayer of TMGa and TMIn on Si, GaAs, or Au is observed with an incident wavelength of 193 and 226 nm ; direct absorption by the absorbed molecules occurs at this wavelength. A 355 nm, photodissociation does not occur.The photodissociation dynamics of organometallic compounds (tetramethyltin, trimethylgallium, trimethylindium and dimethylzinc) absorbed on a quatrz substrate at 100 K have been studied by time-of-flight massspectrometry, detecting mainly CH_3 photofragments.