915 MHz高功率MPCVD装置制备大面积高品质金刚石膜

Large Area High Quality Diamond Films Deposition by 915 MHz High Power MPCVD Reactor

采用自行研制的915MHz/75kW高功率微波等离子体化学气相沉积(MPCVD)装置,在输入功率60kW,沉积气压20kPa的条件下制备了直径5英寸的大面积自支撑金刚石膜,并对金刚石膜的厚度,热导率,线膨胀系数,结晶质量,光学透过率等参数进行了表征。实验结果表明,制备的大面积自支撑金刚石厚膜均匀完整,相关性能参数达到较高水平,具有较好质量。热学级金刚石膜的生长厚度超过5mm,生长速率达到12.5μm/h;室温25℃热导率2010W·m-1·K^-1,180℃条件下的热导率仍达到1320W·m^-1·K^-1;室温25.4℃时线膨胀系数为1.07×10^-6℃^-1,300℃时升高至2.13×10^-6℃^-1。光学级金刚石膜的生长厚度接近1mm,生长速率约为2.3μm/h,厚度偏差小于±2.7%;双面抛光后的金刚石膜厚度约为700μm,其Raman半峰宽为2.0cm^-1,PL谱中未出现明显与氮相关的杂质峰;其光学吸收边约为223nm,270nm处的紫外透过率接近60%,在8~25μm范围内的光学透过率超过70%。

Thick polycrystalline free-standing diamond films of 5 inch in diameter were deposited by a self-made 915 MHz/75 kW high power microwave plasma chemical vapor deposition(MPCVD)system with input power of 60 kW and deposition pressure of 20 kPa.The thickness,thermal conductivity,coefficient of thermal expansion,quality and optical transmission were characterized.The results indicate that the deposited thick free-standing diamond films are uniform,intact and high quality,their relevant performance parameters reaching a high level.Such as the thermal grade diamond film,its thickness is more than 5 mm with growth rate of about 12.5μm/h and coefficient of thermal conductivity of about 2010 W·m-1·K-1 at 25℃and 1320 W·m^-1·K^-1 at 180℃as well as coefficient of thermal expansion of 1.07×10^-6℃-1 at 25.4℃and 2.13×10^-6℃^-1 at 300℃.The thickness of the as-grown optical grade diamond film is close 1 mm with growth rate of about 2.3μm/h and thickness deviation less than±2.7%.The double polished diamond film is about 700μm and possesses excellent characteristics such as FWHM of Raman peak of only 2.0 cm^-1,a cutoff wavelength of 223 nm,UV transmission at 270 nm near 60%,as well as transmission more than 70%in the 8-25μm range.