Effects on low energy ion irradiation for synthesis of carbon nitride thin films

以碳靶为靶材，采用电子回旋共振(ECR)等离子体溅射方法，在不同工艺参数下制备了氮化碳薄膜。重点考察了衬底偏置电压、等离子体气氛、微波输入功率、衬底材料和衬底温度等工艺参数。用XPS、FT-IR、拉曼光谱分析了氮化碳薄膜中氮原子和碳原子的氮原子浓度(N/C原子比)和化学键结构(N-spc、N-sp2C、N-sp3c)。氮化碳薄膜的氮浓度、化学键结构等性质明显依赖于衬底的正、负偏压。在纯氮等离子体、衬底偏压为-40V、微波输入功率为200W的条件下，N/C原子比达到0.35。这些公司不会在低于-50V的衬底偏置电压下沉积，因为重新溅射沉积的公司。公司中的氮原子主要与sp3和sp2杂化碳化学键合。随着工艺参数中氮气分压和微波输入功率的增加，(N-SP^3C)/(N-SP^2C)的峰面积比增大。在工艺参数中降低衬底偏置电压会增加(N-sp^3C)/(N-sp^2C)的峰面积比。这些结果影响了ECR等离子体中N_2离子密度的增加。这些实验结果表明，控制在40 eV以下的低能氮离子和高离子通量密度的离子轰击生长的薄膜表面有利于合成亚稳态结晶氮化碳薄膜。讨论了形成亚稳态相的生长模型，并与亚注入模型进行了比较。实验结果表明，亚注入模型可以定性地应用于亚稳相氮化碳薄膜的形成。

Carbon nitride thin films were synthesized by electron cyclotron resonance (ECR) plasma sputtering method with a carbon target and under various process parameters. Especially, substrate bias voltage, plasma atmosphere, microwave input power, substrate materials and substrate temperature as the process parameters were investigated. The nitrogen concentration (N/C atomic ratio) and chemical bond structure (N-spC, N-sp^2C, N-sp^3C) of nitrogen and carbon atoms in synthesized thin films were discussed with XPS, FT-IR, Raman spectroscopy.The nitrogen concentration, chemical bond structure and other properties of carbon nitride thin films were clearly dependent on the positive and negative bias voltage applied to the substrate. The N/C atomic ratio reached to 0.35 at pure nitrogen plasma, -40V in substrate bias voltage, 200 W in microwave input power. The firms do not deposit at less than -50V of substrate bias voltage, because of re-sputtering the deposited firm.Nitrogen atoms in the firms are chemically bonded mainly with sp^3, and sp^2 hybridized carbon. Increasing the nitrogen partial pressure and microwave input power in process parameter lead up to increase the peak area ratio of (N-sp^3C)/(N-sp^2C). Decreasing the substrate bias voltage in process parameter leads to increase the peak area ratio of (N-sp^3C)/(N-sp^2C). These results were affected the increase of the N2+ ion density in the ECR plasma.These experimental results demonstrate that the ion bombardment onto the growing film surface with controlled low energy nitrogen ion of below 40eV and high ion flux density is favorable to synthesize of the metastable crystalline carbon nitride films.A growth model for formation of metastable phase in comparison between these experimental results and subimplantation model were discused. Our experimetnal results were implied that the subimplantaiton model could be applied qualitatively for the formation of metastable phase carbon nitride films.