人造金刚石单晶薄膜的制备及表面形貌优化

Preparation and Surface Optimization of Synthetic Diamond Single Crystal Film

人造金刚石作为一种高效的热管理衬底,在宽禁带半导体电子器件领域具有广泛的应用前景。然而微波等离子体化学气相沉积(MPCVD)法外延金刚石单晶的生长速率慢,表面粗糙度高,难以满足半导体器件的衬底需求。对此,本文采用MPCVD法制备金刚石单晶薄膜,通过分阶段生长监控样品的生长速率,结合显微镜照片和AFM表征样品的表面形貌和表面粗糙度,根据拉曼光谱和XRD分析外延薄膜的晶体质量,最终采用高/低甲烷浓度的两步法外延工艺,实现了金刚石单晶薄膜的高速外延,生长速率达到20μm/h,同时获得了较为平整的表面形貌。本文所研究的甲烷调制两步法外延工艺能够起到表面形貌优化的作用,有利于在后续的相关器件研发中提供平整的金刚石衬底,推动高功率电子器件的发展。

Single crystal diamond film has been developed as high efficiency thermal management substrate,which has a promising potential in the field of wide bandgap semiconductor electronic devices.However,the slow production yield and rough surface of diamond film grown by microwave plasma chemical vapor deposition(MPCVD)make it unavailable as the substrate for semiconductor devices.In this work,single crystal diamond films were grown by MPCVD step by step,of which the growth rate was compared and the surface morphology and crystal quality was estimated by photos,XRD,AFM and Raman measurements.High-speed single crystal epitaxial diamond layer which could reach 20μm/h with smooth surface was acquired by two-step growth technique of adjusting methane concentration.It is beneficial to solve the problems of rough surface morphology and processing difficulties of diamond epitaxial films in the subsequent fabrication of related electronic devices,so as to support the development of high power electronic devices.