Hardness and Structure of a-CN_x Films Synthesized by Chemical Vapor Deposition

Abstract

Mechanically hard a-CN x films were synthesized using a combination of ion bombardment and the chemical vapor deposition process using the dissociative excitation reaction of BrCN with Ar metastable atoms. Nanoindentation tests disclosed that the indentation hardness, Young's modulus and elastic recovery increased with increasing ion-accelerating voltage. Moreover, the degree of flow among clusters decreased in the ion-bombarded sample. The D (disordered)-band absorption on an infrared absorption spectrum was replaced by a C–N absorption assigned to the tertiary aromatic amine. These results suggest that the internal and external structures of the carbon nitride cluster change from the two-dimensional order to the three-dimensional order of C–N. The structure of hard a-CN x is clearly distinguishable from nitrogen-containing diamond-like carbon.

Dissociative Excitation Process of BrCN in the ECR Plasmas of Rare Gases

“…These high ratios have been rationalized in the case of MW discharge flow of Ar as the precursors of film formation are predominantly the ground (X 2 Σ + ) state of CN radicals [18,19]. (b) When H 2 O molecules are removed from the reaction system and the RF-bias voltage is applied to the substrate, the hardness of the films reaches as high as 36±10 GPa [13,16,17]. (c) High efficiency of electricfield emission have been shown for a-CN x :H films when they are deposited onto the Al-doped single crystal whiskers of ZnO [14,15,22].…”

“…We have applied these reactions to the synthesis of a-CN x and a-CN x :H thin films, where the microwave (MW) discharge flow of Ar [11][12][13][14][15][16][17][18][19] and the ECR discharge flows of Ar [20,21] and He [22] have been used. These films have the following characteristics.…”

Deposition of mechanically hard amorphous carbon nitride films from decomposition of BrCN. Effects of substrate cooling and pulsed rf-bias voltage

“…Since these radicals deposit onto the substrate in our CVD system, the [N]/([N] + [C]) ratio becomes high (30-50%). Further, mechanically hard a-CN x films can be formed when the H 2 O molecules are removed from the reaction system and the RF bias voltage (ÀV RF ) is applied continuously to the substrate [9,10]. Microhardness measurement using the Vickers indenter under the maximum load of 7 mN has revealed that the maximum hardness of the a-CN x film is 21.6 GPa which is obtained under the deposition condition of ÀV RF =50 V.…”

“…1 shows the schematic diagram of the MWCVD apparatus used in the present study. The apparatus was essentially the same as that used in our previous studies [6][7][8][9][10]. It consisted of a stainless steel vacuum chamber with the internal diameter of 101.6 cm, which was evacuated to 63 · 10 À3 Torr by using a combination of mechanical booster (110 m 3 /h) and oil rotary (600 L/min) pumps.…”

Targeting mass-selected cluster ions for the deposition of advanced carbonaceous materials using an inductively coupled plasma

“…However, tuning selectively 4 cluster ions has still to be addressed. Note, there are many reports dealing with either high 5,6 mass carbon clusters and low 7,8 mass cluster ions but very few relate to 3-10 carbon atom systems. The present work addresses the fragmentation, in an inductively coupled rf plasma, of the tricyclic hydrocarbon adamantane and the significance of this with respect to film deposition.…”