Study on boron distribution in boron-doped diamond synthesized at HPHT conditions

Diamond, as a wide-bandgap semiconductor, is expected to enable miniaturized applications for high-frequency and high-power electronics. One of the problems affecting the application of boron-doped diamond (BDD) lies in the inhomogeneous distribution of their boron impurities. This article reports the synthesis of BDDs in the Fe-TiB-C system. The growth sectors as well as the depth distribution characteristics of boron impurities were focused on. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy demonstrated that the boron content decreases along the (111), (113), and (100) directions in the growth sectors. Raman and Hall effect measurements of the crystals before and after polishing showed a higher boron content on the surface of the BDD than that of in the interior. The results of X-ray Photoelectron Spectroscopy (XPS) depth profiling responded that the contents of both B-C and B-O bonds on its surface decreased with the increase of etching depth. This work is an important reference for predicting the distribution pattern of boron impurities, which will be of great significance for the modernization and implementation of BDDs.