摘要
采用超声分子束和时间分辨质谱技术,对氯分子与Si(111)、GaAs(100)和InP(100)等表面的激光诱导蚀刻反应中的脱附动力学进行了研究.在560nm和355nm脉冲激光辐照下,测量了主要脱附产物的飞行时间谱随激光能量密度(E_L)的依赖关系.发现对所研究的体系均存在激光能量密度反应阈值.数据拟合表明,主要脱附反应产物均具有热平衡的Maxwell-Boltzmann速度分布.进一步分析指出,在超声分子束和脉冲激光条件下,反应中间产物的脱附为蚀刻反应的主要速率控制步骤,并且以激光诱导热脱附为主要机理。
The desorption dynamics of reaction products in laser induced chemical etching of Si(111), GaAs(100) and InP(l00) surfaces by chlorine molecules is studied using a CW supersonic molecular beam and a time-resolved mass spectrometry. The time-of-flight (TOF) spectra of the major desorbed species have been measured as a function of laser flunce (E_L) under 560 nm and 355 nm pulsed laser irradiations and it is found that there exist laser fluence thresholds for the investigated reaction systems. The analysis shows that the measured TOF spectra of desorbed species fit a Maxwell—Boltzmann distribution pretty well. It is pointed out that the laser—induced desorption of the reaction intermediates is the rate—limiting step of the chemical etching reactions under molecular beam and pulsed laser conditions, and the desorption process may be described as the laser induced thermal desorption.
基金
国家自然科学基金
