N掺杂对a-SiC：H基介质扩散阻挡层结构及性能的影响

Effect of N-doping on the microstructure and properties of amorphous SiC:H diffusion barrier films

用射频等离子增强化学气相沉积技术(RF-PECVD)制备非晶碳化硅(a-SiC:H)和不同掺氮量的碳化硅基(a-SiCNx:H)介质薄膜.采用傅里叶红外光谱(FIRT),X射线光电子谱仪(XPS),纳米压入仪(Nano IndenterR○-XP),Agilent 4294A高精度阻抗分析仪,俄歇能谱仪(AES)和场发射高分辨透射电镜(HRTEM)表征氮掺杂对碳化硅基薄膜化学键组成、微观结构、机械性能、介电常数和阻挡铜扩散性能的影响.实验结果表明:通过控制薄膜的氮含量可实现其介电常数在3.8—5.2范围内可调.随着反应源中氨气(NH3)流量的增加,碳化硅基薄膜中Si—N和C—N化学键比例增加以及由此导致的薄膜微观结构致密化是氮掺杂显著提高碳化硅基薄膜机械性能、热稳定性和阻挡铜扩散性能的机理.

Hydrogenated amorphous a-SiC：H and a-SiCN：H with different nitrogen-concentration dielectric barrier films are prepared using the plasma-enhanced chemical vapor deposition technique （RF-PECVD）. The chemical and structural nature,mechanical property,dielectric constant and copper diffusion property of these films are characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy measurement,nano-indentation,Agilent 4294A precision impedance analyzer,Auger electron spectroscopy and field emission transmission electron microscopy. The results indicated that the dielectric constand of the film can be adjusted btween the values of 3.8 and 5.2 by controling the NH3/3MS ratio. With the increasing of NH3/3MS ratio,the concentration of Si-N and C-N bond structure is gradually increase and micro-structure of the film becomes more dense,which is the mechanism of the improvement in the mechanical property,thermal stability and copper diffusion property of the a-SiC：H based film produced by N-doping.