SUB-20 PS ECL CIRCUITS WITH HIGH-PERFORMANCE SUPER SELF-ALIGNED SELECTIVELY GROWN SIGE BASE (SSSB) BIPOLAR-TRANSISTORS

This paper describes a high maximum frequency of oscillation f(max) self-aligned SiGe-base bipolar transistor technology, based on a self-aligned selective epitaxial growth (SEG) technology including graded Ge profile in an intrinsic base and link-base engineering using a borosilicate glass (BSG) sidewall structure. The transistor is a new self-aligned transistor, which we call a Super Self-aligned Selectively grown SiGe Base (SSSB) bipolar transistor, The 1st step of the annealing (800 degrees C, 10 min) was performed for the diffusion of boron from the BSG film, before the deposition of an emitter polysilicon film. The 2nd step of the annealing (950 degrees C, 10 sec) of emitter drive-in was carried out, which enabled us to obtain sufficient current gain using insitu phosphorus doped polysilicon as an emitter electrode, Sheet resistance for a link-region more than one order lower than that of the epitaxial intrinsic base was obtained after heat treatment, Base profile (boron and Ge) design, and the 2-step annealing technique have realized cut-off frequency fr of 51 GHz and f(max) of 50 GHz, ECL circuits of 19-psec gate delay have been achieved.