Photodissociation Dynamics on Surface Probed by Vacuum uv Laser.

用X射线和紫外光电子能谱技术研究了三甲基镓在硅、金和铝衬底上的热解和光解。在Si(111)衬底上，镓金属和CH_n自由基热分解到670K，在多晶金衬底上观察到镓金属，而在470K时CLS信号消失。单层Ga(CH_3)_2在266 nm处的光解离给出了CH_n自由基和Ga金属在硅片上的XPS光谱，而在355 nm处没有观察到分解。在100 K下，193或351 nm的激光照射在硅片上的多层Cl2或CH_3CL导致这些分子的光解离和光刻蚀产物的形成。测量了光碎片(Cl、CH3)和刻蚀产物(SiCl2、SiCiC2)的动能分布。用共振增强多光子电离技术观测了HCl和HBr在真空紫外区光解产生的氢原子光解碎片的多普勒谱，确定了较高电子态的对称性。烷基氯(R=CH3，C2H5，C3H7和C4H9)，氯甲烷(CHNCL&lt；4-n&gt；)和氯氟甲烷(Cf_nCL&lt；4-n&gt；)在真空紫外区光解。用共振增强多光子电离技术探测了氯原子的光碎片。电子态的对称性是由光碎片的角分布确定的。

Pyrolytic and photolytic dissociation of trimethylgallium on Si, Au, and Al substrates was studied by X-ray and UV photoelectron spectroscopy technique. On an Si (111) substrate, gallium metal and CH_n radicals are deposited by pyrolytic dissociation up to 670 K. On a polycrystalline Au substrate, gallium metal was observed while Cls signal disappeared at 470 K. Photodissociation of monolayered Ga(CH_3)_2 at 266 nm gives XPS spectra for CH_n radicals and Ga metal on the Si wafer while at 355 nm no decomposition was observing.Laser irradiation at 193 or 351 nm of a multilayer of Cl_2 or CH_3Cl on an Si wafer at 100 K leads to both photodissociation of these molecules and formation of photoetching products. The kinetic energy distributions of photofragments (Cl, CH_3) and etching products (SiCl, SiCiC_2) were measured. The kinetic energy distribution of Cl or CH_3 is bimodal for the case of thin deposition of parent molecules on substrates.The Doppler profiles of the hydrogen atom photo fragments from the photodissociation of HCl and HBr at vacuum UV region are observed to determine the symmetries of the higher electronic states by using a resonance enhanced multiphoton ionization technique.Alkyl chlorides (R = CH_3, C_2H_5, C_3H_7, and C_4H_9), chloromethanes (CH_nCl_<4-n>), and chlorofluoromethanes (CF_nCl_<4-n>) are photodissociated at vacuum UV region. The chlorine atom photo fragments are detected by a resonance-enhanced multiphoton ionization technique. The symmetries of the electronic states are determined from angular distributions of photofragments.