Low Temperature Fabrication of Diamond Films by CVD Method with Laser Induced Surface Reaction

设计并制作了热解吸装置和激光诱导解吸装置。该仪器有4种入射窗口（入射角度0- 600度），XYZθ样品级（探测角度0- 800度），飞行时间和/或四极杆质谱仪，以及高达1400℃的样品加热系统。对样品表面进行修饰的加药系统是通过热W管的热裂解系统，热W管作为气体导入管的一部分被取代，因为气体分子可以在热W管内壁上解离。因此，我们可以选择一种方法来控制样品表面终止，利用热样品表面分子的热解离或热裂解系统产生的原子通量。用该装置进行热解吸和激光诱导解吸时，样品表面的悬空键通过氘在1300K温度下的热解离而终止。然后，在d端表面检测氘分子的热解吸谱。热解吸光谱结果证实了给药后样品表面的终止结构。在热解吸测量结果和推测的基础上，利用Nd: YAG脉冲激光（基波-四谐波）检测了激光诱导解吸光谱。试图测定端h、端CO、端CO2从端o型金刚石晶体中解吸H2的情况。将样品加热至200℃，解吸物理吸收的H2O和/或CO后，将不同波长和能量密度的激光脉冲照射到样品上。在基频、二频和三频的情况下，我们没有检测到任何解吸光谱。虽然我们可以检测到四次谐波的脱附光谱，但这不是由于激光在表面键处诱导反应的脱附，而是由于激光脉冲在金刚石晶体缺陷处的吸收导致样品加热的热脱附。少

The novel apparatus was designed and manufactured for thermal desorption and laser induced desorption. This apparatus has 4 kinds of inlet window through which laser beam can irradiate onto the sample (incident angle : 0-60o), XYZθ sample stage (detection angle : 0-80o), time-of-flight and/or quadrupole mass spectrometer, and sample heating system up to 1400oC. The dosing system, by which the sample surface can be modified, is the thermal cracking system through hot W tube which was replaced as a part of gas introduction tube, since the gas molecule can be dissociated on the inner wall of hot W tube. Therefore, we can choose either method to control the sample surface termination, using the thermal dissociation of molecules on hot sample surface or atomic flux generated in thermal cracking system.Using this apparatus both for thermal desorption and for laser induced desorption, the dangling bonds on the sample surface was terminated by the thermal dissociation of deuterium on 1300K sam … More ple. Then, the thermal desorption spectrum of deuterium molecules was detected from the D-terminated surface. The termination structure of sample surface after dosing was confirmed by the result of thermal desorption spectra.On basis of the results and speculation of thermal desorption measurement, laser induced desorption spectrum was detected using Nd : YAG pulse laser (fundamental - 4th harmonic wave). H2 desorption of H-terminated, CO and CO2 from O-terminated diamond crystal tried to be measured. After the sample was heated up to 200℃ to desorb physiabsorbed H2O and/or CO, a variety of lased wavelength and energy density of laser pulses were irradiated onto the sample. In case of the fundamental, 2nd, and 3rd harmonic wave, we could not detect any desorption spectra. Although we could detect desorption spectra in case of the 4th harmonic wave, it was not due to the desorption by the laser induced reaction at the surface bond, but due to the thermal desorption by the sample heating as a result of the absorption of laser pulse at the defects in diamond crystals. Less