A 60-GHz f(T) super self-aligned selectively grown SiGe-base (SSSB) bipolar transistor with trench isolation fabricated on SOI substrate and its application to 20-Gb/s optical transmitter IC's

A 60-GHz cutoff frequency (f(T)) super self-aligned selectively grown SiGe- base (SSSB) bipolar technology is de,eloped, It is applied to 20-Gb/s optic al fiber transmitter IC's, Self-aligned bipolar transistors mutually isolat ed by using a BPSG-filled trench were fabricated on a bond-and-etchback sil icon-on-insulator (SOI) substrate to reduce the collector-substrate capacit ance Ccs. The SiGe base was prepared by selective epitaxial growth (SEG) te chnology. A 0.4-mu m wide emitter was used to reduce the junction capacitan ces. The maximum cutoff frequency fT and the maximum frequency of oscillati on f(max) were 60 and 51 GHz, respectively. By using this technology, Si-IC 's for an optical transmitter system were made, such as a selector (a multi plexer without input and output retiming D-type hip-hops (D-F/F's)], a mult iplier, and a D-F/F, An internal highspeed clock buffer circuit achieves st able operation under a single clock input condition in the selector and the multiplier IC's. Their stable operation was confirmed up to 20 Gb/s, The s elector IC for data multiplexing operates at over 30 Gb/s.