Vol. 56 No. 3

Material Science and Technology of Japan, 56（2019）109～112

25

Regular Paper
Estimation of Optical Emission Spectroscopy on synthesizing B-doped
Diamond using Mode Conversion Type Microwave Plasma CVD
Asuka SUZUKI1, Takuya MARUKO1, Tomoya SAKUMA1,2, Yoshihiro TAKAHASHI3,
Yukihiro SAKAMOTO3
1

Graduate school,275-0016 ,Japan

2

Ogura jewel industry Co., Ltd., 5-7-12, Omori-kita, Ota-ku, Tokyo 143-0016 ,Japan

3

Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino-shi, Chiba, 275-0016, JapanChiba

InstituteofTechnology,2-17-1,Tsudanuma,

Narashino-shi,Chiba

Received Nov. 21, 2018; Accepted Feb. 27. 2019
Abstract
In this paper, we investigate the influence of plasma state on volume resistivity of B-doped diamond (BDD). It
is difficult to prepare BDD of required volume resistivity. Various researches have been studied on the control of theresistance value of BDD. Thus, systematic research on the relationship between volume resistivity and B in plasma isnecessary. Therefore, plasma during growth is measured by Optical Emission Spectroscopy (OES) and make clear
relationship between emission species and resistance value. OES, peaks of B (249.7 nm), BH (433.1 nm), BO(436.3nm), Hα, Hβ, CH and C2 were observed for each condition. Electrical resistivity measurements by the four-pointprobe method, minimum volume resistivity of 0.17 Ω·cm was obtained. With increasing B containing emission
species such as B and BH peaks in OES spectra, volume resistivity is decreased. It suggested that B system emission
species in OES spectra influences volume resistivity of BDD.
Keywords: CVD, B-doped diamond, OES, volume resistivity, microwave

1.

Introduction

the time of synthesis, it is possible to synthesize BDD by using

B-doped diamond (BDD) is diamond imparted withbubbling tank as a carrier gas. In this study, we measured of

conductivity in addition to having excellent properties ofplasma using OES (Optical Emission Spectroscopy) during

diamond. There are few examples of practical applications

synthesis and investigated on the relationship with volume

compared to general diamond. This is due to the fact that there

resistivity.

are many points that are not clarified concerning the control of2.

parameters of BDD. In particular, various researches have beenExperimental methoddone on the control of the resistance value of BDD, and both

Boron-doped diamond films were synthesized using thehave tried to control the resistance value, but there are large

mode-conversion type microwave plasma Chemical Vapor

variations [1]. For BDD synthesis, synthesis is carried out using

Deposition (CVD) apparatus [8]. Si (P-type, 8-12 Ω·cm)

a gas B source that is highly toxic and flammable, such as B2H6

substrate was scratched by diamond powder and then cleaned[2,3] and B(CH3)3 [4,5], but the gas B source needs security

ultrasonically in acetone solution. During synthesis, plasmasystems.

states were estimated using optical emission spectroscopy (OES)(US2000+UV-VIS/Ocean Optics). The surface of the deposits

On the other hand, liquid B sources, in which B2O3 [6]and H3BO3 are dissolved in pure water and alcohol solution as B

wassources [7], are relatively safe and no need security systems. At(TOPCON/SM-300). Qualities of the deposits were estimated by(109)observedby

Scaning

ElectronMicroscope(SEM)