[20p-H103-1~21] 6.2 Carbon-based thin films

△ [20p-H103-15] a-BCN films synthesized from tri-methylborazine

〇Nasa Kawagoshi¹, Tetsuya Yamamoto², Masayuki Nakano³, Yoshinao Iwamoto⁴, Makoto Matsuo⁴, Junko Hieda¹, Naoto Ohtake¹, Hiroki Akasaka¹ (1.Tokyo Inst. Tech., 2.Nippon Shokubai Co., Ltd., 3.Tokyo Natl. Col. Tech., 4.i-Motto Co., Ltd.)

Keywords:Amorphous Boron Carbon Nitrogen film,Trimethyl borazine,Hardness

Hydrogenated amorphous Boron Carbon Nitrogen (a-BCN) film has many excellent mechanical properties such as high wear resistance, high hardness, and reactivity with iron. Therefore, a-BCN film is expected the mechanical applications. Amorphous BCN film is deposited by reactive sputtering method using B₄C target and N₂ gas or by chemical vapor deposition (CVD) method using trimethyl boron and N₂ gas. However, it is difficult to introduce N atom into a film effectively to reach to 1 in the ratio of B/N by these methods. The nitrogen atom introduction into raw materials molecules is effective to incorporate N atom into a film. Therefore, in this study, a-BCN film was deposited from trimethyl borazine as raw materials and evaluated the composition of the film and a mechanical characteristic. Amorphous BCN film was deposited on Si(100) by the pulse plasma CVD method. Obtained film was evaluated for the mechanical properties by nano indentation test, and the chemical composition by the X-rays photoelectron spectrum (XPS) method. To obtain the hardness, a high-resolution indenter with a Vickers diamond tip was used. The elements detected were observed from survey spectrum of the XPS analysis obtained over each elemental energy range of 0–1100 eV with an energy resolution of 1.5 eV. From XPS spectrum of survey analysis, four elements of C, B, N, and O were included in obtained film and other elemental peaks weren’t presented. From XPS spectra of the narrow range measurements for specific evaluations, chemical composition was evaluated. The elemental composition except hydrogen of film was B 27.7 , C 20.6 , N 13.5 , O 37.7 and Si 0.5 at.%. Although atomic concentration of B is the same as that of N of N,N',N''-trimethyl borazine as raw materials, the ratio of the concentration of N of the obtained a-BCN film was lower than raw materials. A result of nano indentation tester, the indentation hardness was 1.06 GPa and the a-BCN film is relatively soft film compared with previous reports. Our XPS results indicated containing of diffused oxygen atoms in to the film. And the small peak of B-B metallic bonding was observed at XPS spectrum for B1s. Hence, one of the reason for the low hardness may be that the diffused oxygen atoms from the surface bonded with boron, and the B-B bonding, because all boron atoms did not bond with nitrogen or carbon atoms.