4H-SiC高温激活退火对F离子扩散的影响

Effect of High-Temperature Activation Annealing on F Ion Diffusion in 4H-SiC

摘要: 离子注入工艺作为SiC MOSFET/Diode器件制造过程的重要工艺过程，离子注入后激活退火的温度直接影响注入后晶格损伤的修复效果以及离子激活的程度，离子注入和激活退火一直是研究的热点和难点。本文主要研究了离子注入后激活退火温度对离子扩散至SiC/SiO₂界面处的浓度的影响，离子注入在4H-SiC(0001)面进行，注入元素F，离子注入能量25 KeV，浓度5E13 cm⁻²，在离子注入后，分别在500℃、700℃、900℃、1100℃下进行激活退火2 min，而后通过二次离子质谱法(SIMS)分析不同温度激活退火后F元素扩散至SiC/SiO₂界面处的浓度，以及F元素扩散到背面(C-face(0001))的浓度，实验结果表明随着激活退火温度的增加，SiC材料表面的元素浓度也随之增加，实验结果发现在700℃激活退火时，SiC/SiO₂界面处F元素浓度升高明显，并且扩散至C面的元素浓度相对于离子注入激活退火前的样品基本无变化。

Abstract: The ion implantation is one of the most important processes in SiC MOSFET/Diode devices manufacturing. The ion activation temperature after implantation results has direct impact on the performance of lattice damage repairing and the degree of ion activation. The ion implantation process and activation annealing are hot and difficult research spots. In this paper, the effect of activation annealing temperature on the concentration of SiC/SiO₂ interface after ion implantation was studied. The ion implantation was carried out on the 4H-SiC (0001) surface, element F was implanted, the ion implantation energy was 25 KeV and concentration was 5E13 cm⁻². And then the samples were annealed at 500˚C, 700˚C, 900˚C and 1100˚C for 2 min, respectively. The concentration of F in Si-face and the diffusion of F element to the back surface (C-face (000-1)) with different activation annealing temperature were also monitored by secondary ion mass spectroscopy (SIMS). It finds that the surface ion concentration increased as the activation annealing temperature increased. The experimental results showed that when activation annealing is at 700˚C, the F ion concentration was increased at SiC/SiO₂ interface, and the F ion concentration diffused to the 4H-SiC C-face is substantially unchanged from the sample without ion-implantation activation annealing.