直喷式直流电弧等离子化学气相沉积法金刚石单晶外延层制备研究

Growth of Diamond Single Crystal Epitaxial Layer by DC Arcjet Plasma Chemical Vapor Deposition at Blow-down Mode

采用非循环直流喷射(直喷式)直流电弧等离子化学气相沉积法,在Ar/H2/CH4气氛下,成功制备了金刚石单晶外延层。试验采用的是3 mm×3 mm×1.2 mm的高温高压Ib型金刚石单晶衬底。研究了不同衬底温度和甲烷浓度对金刚石单晶外延层的形貌,速率和晶体质量的影响。采用光学显微镜,激光共聚焦表征了样品的形貌,利用千分尺测量其生长速率,利用Raman表征其晶体质量,采用OES诊断Ar/H2/CH4等离子气氛下C2、CH与Hβ的相对浓度。研究表明,温度和甲烷浓度对单晶刚石形貌和质量产生了明显的影响。在衬底为温度980℃,甲烷浓度在1.5%的条件下,生长速率达到了36μm/h,并且晶体质量较好(半高宽仅为1.88 cm-1)。同时发现生长参数对金刚石单晶外延层的生长模式有着显著地影响。

Diamond single crystal epitaxial layers on commercial 3. 5 mm × 3. 5 mm × 1. 2 mm type Ib（100） HTHP substrate were obtained by DC-Arc plasma jet chemical vapour deposition（CVD） method at blow-down mode. The influences of parameters such as methane concentration and substrate temperature on morphology, quality and growth rate of SCD were investigated by OM,confocal laser scanning microscopy,surface profilometer,Raman and micrometer. The relative concentrations of C2,CH and Hβin the plasma close to the substrate generated by the activation of the H2/ Ar / CH4gas mixtures were diagnosed by Optical Emission Spectra（OES）. The results show that the growth rate,quality,and surface roughness of SCD were affected by the parameters extremely and the growth rate can be as high as 36 μm / h without the degradation of the quality. The FWHM of the characteristic diamond Raman peak for a smooth（100） flat surface SCD layer achieved under the optimum condition was around 1. 88 cm-1. DC-Arc Plasma Jet CVD technology can be used as an alternative and complementary method for preparing the single crystal diamond plates.