Improving the high frequency performance of SiGe HBT with new lateral structure and process

After the shortage of the conventional lateral structure of SiGe HBT was analyzed, A new lateral structure was presented. In the meantime, the new fabrication process named buried metal self-aligned technique was designed. The measured frequency features show that the cut-off frequency f_T of the device up to 12.3GHz and the maximum oscillation frequency f_max achieves 5.7GHz. Compared to the conventional lateral structure and process, the values of f_T and f_max of SiGe HBT based on the new lateral structure and process have been increased 17% and 18.75% respectively. This indicates that the new lateral structure and buried metal self-aligned process is effective to improve the high frequency performance of SiGe HBT