Growth and Electrical Properties of High-Mobility Boron-Doped Single Crystal Diamond via Microwave Plasma Chemical Vapor Deposition

doi:10.16553/j.cnki.issn1000-985x.2025.0060

Abstract

Abstract: High-crystallinity and high-mobility boron-doped single crystal diamond films are the key to realizing high-voltage and high-power electronic devices. In this study， microwave plasma chemical vapor deposition （MPCVD） technology was employed， combined with a two-step growth method and a low-temperature oxygen-assisted growth strategy， to successfully prepare high-mobility boron-doped single crystal diamond films with extensive electrical property tuning. The films were characterized using X-ray diffraction （XRD）， Hall effect measurements， and X-ray photoelectron spectroscopy （XPS）. XRD analysis reveals an XRD peak full width at half maximum （FWHM） of less than 60″， indicating excellent crystalline quality. Hall effect measurements demonstrats precise control over hole concentrations ranging from 10¹⁴ to 10¹⁷ cm^-3， with a maximum room-temperature hole mobility exceeding 1 400 cm²/（V·s）， reaching the international advanced level. XPS characterization confirms successful boron incorporation and reveals a direct correlation between crystalline perfection and high carrier mobility， identifying high crystalline quality as a key factor for achieving high mobility. This work establishes a robust technological framework for synthesizing high-quality boron-doped diamond films， providing key materials for the development of high-performance diamond devices.

Key words: single crystal diamond; epitaxial growth; boron doping; MPCVD; electrical property; mobility; power device

CLC Number:

O782

HU Yushuo, YANG Guojian, CAO Guangyu, LIU Cien, ZHANG Xing, LONG Hao, XU Xiangyu, ZHANG Hongliang. Growth and Electrical Properties of High-Mobility Boron-Doped Single Crystal Diamond via Microwave Plasma Chemical Vapor Deposition[J]. Journal of Synthetic Crystals, 2025, 54(9): 1566-1573.

Figures/Tables 6

Fig.1 Schematic diagram of two-step growth

Table 1 Basic parameters of boron-doped single crystal diamond samples

Sample	1#	2#	3#	4#
B/C ratio/ppm	10	50	100	400
Size/mm³	6 $×$ 6 $×$ 0.035	6 $×$ 6 $×$ 0.035	6 $×$ 6 $×$ 0.035	6 $×$ 6 $×$ 0.063
Hole concentration/cm^-3	4.8 $×$ 10¹⁴	1.5 $×$ 10¹⁵	1.0 $×$ 10¹⁶	3.5 $×$ 10¹⁷

Table 1 Basic parameters of boron-doped single crystal diamond samples

Sample	1#	2#	3#	4#
B/C ratio/ppm	10	50	100	400
Size/mm³	6 $×$ 6 $×$ 0.035	6 $×$ 6 $×$ 0.035	6 $×$ 6 $×$ 0.035	6 $×$ 6 $×$ 0.063
Hole concentration/cm^-3	4.8 $×$ 10¹⁴	1.5 $×$ 10¹⁵	1.0 $×$ 10¹⁶	3.5 $×$ 10¹⁷

Fig.2 Morphology of boron-doped single crystal diamond. （a） Optical microscope image of boron-doped single crystal diamond film；（b） SEM image of boron-doped single crystal diamond film；（c），（d） AFM images of boron-doped single crystal diamond film

Fig.3 Characterization of the crystal quality of boron-doped single crystal diamond. （a） XRD characterization of boron-doped single crystal diamond；（b） Raman spectroscopy characterization of boron-doped single crystal diamond；（c） optical transmittance of the boron-doped single crystal diamond film；（d） Tauc plot of the boron-doped single crystal diamond film

Fig.4 Characterization of the electrical properties of boron-doped single crystal diamond. （a） Graph of the relationship between the hole concentration and mobility of the boron-doped single crystal diamond film and the boron-to-carbon ratio；（b） comparison between the work of this study and international research work

Fig.5 XPS characterization of boron-doped single crystal diamond films. （a） C 1s peak spectrum of the boron-doped single crystal diamond film；（b） valence band diagram of the boron-doped single crystal diamond film；（c） graph of the relationship between EB and C 1s shift with the change of hole concentration；（d） schematic diagram of the energy band of the boron-doped single crystal diamond

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