HfO_(2)介质薄膜表面原位低温沉积石墨烯研究

Study on In-situ Low-temperature Deposition of Graphene on the Surface of HfO_(2) Dielectric Film

研究了高k介质HfO_(2)薄膜制备工艺和石墨烯原位沉积工艺的结合。采用真空电子束蒸镀在重掺杂Si衬底上室温沉积HfO2薄膜,并对薄膜样品分别进行400、450、500℃的恒温90 s快速退火处理。AFM测试结果表明,退火处理后HfO2薄膜表面的均方根粗糙度均未高于0.30 nm,处于较低水平;XRD测试结果表明,不同温度的退火处理并未使HfO2薄膜结构发生改变,样品均为无定形结构;阻抗测试结果显示,三组薄膜样品的相对介电常数均大于21且介电损耗水平均较低,介电性能良好。以室温电子束蒸镀制备的HfO_(2)薄膜为基底,利用PECVD在400、450、500℃低温条件下原位生长石墨烯。AFM和拉曼测试结果表明,500℃下沉积的石墨烯样品表面平坦度最高且层数在10层以内,实现了石墨烯器件绝缘介质层与有源层制备工艺的良好结合。

The combination of preparation process of high-k dielectric HfO_(2)film and in-situ deposition process of graphene was studied.Vacuum electron beam evaporation was used to deposit HfO_(2) film on heavily doped Si substrate at room temperature,and the film samples were rapidly annealed for 90 s at a constant temperature of 400℃,450℃ and 500℃,respectively.AFM test results show that the root mean square roughness of the HfO_(2) film surface after annealing treatment is not higher than 0.30 nm,which is at a low level.XRD test results show that the annealing treatment at different temperatures does not change the film structure,and all the samples are amorphous.Impedance test results show that the relative dielectric constants of the three groups of film samples are greater than 21 and their dielectric loss level is low,indicating that the HfO_(2) films have good dielectric properties.The HfO_(2) film prepared by electron beam evaporation at room temperature was used as the substrate,and graphene was grown in situ by PECVD at low temperature of 400℃,450℃ and 500℃.AFM and Raman test results show that the surface of the graphene sample deposited at 500℃ has the highest flatness within 10 layers,which achieves a good combination of the preparation processes of the insulating dielectric layer and the active layer of the graphene device.