Effects of H2 annealing and polysilicon emitter structure on HFE of n-p-n bipolar junction transistors

This paper presents the effects of H₂ annealing and polysilicon emitter structures on H_FE characteristics of n-p-n bipolar junction transistors. The increase of the number of H₂ annealing steps results in the device performance (H_FE×V_A) improvement by 27.8%, due to the formation of H-Si dangling bonds, which allow the decrease of the base current. In addition, the bilayer of undoped polysilicon deposition/ion implantation and in situ doped polysilicon in the ploy emitters greatly improve the level of H_FE reliability and 1/f noise characteristic. The experimental results of H-Si dangling bond property at the polysilicon grain boundaries and polysilicon interface with the H₂ annealing steps in n-p-n bipolar junction transistor formulation will be also presented.