A 2.4 Gb/s receiver and a 1:16 demultiplexer in one chip using a super self-aligned selectively grown SiGe base (SSSB) bipolar transistor

Abstract

This paper reports a 2.4 Gb/s optical terminal IC that integrates high-speed analog and digital circuits for future optical networks using 60-GHz f/sub T/ self-aligned silicon-germanium (SiGe)-alloy base bipolar transistors. The selective epitaxial growth (SEG) SiGe base was formed by using cold-wall ultra-high vacuum (UHV)/CVD technology. Boron concentration reduction at the SiGe epitaxial layer/Si-substrate interface by using a new treatment prior to SEG leads to electrical characteristics with less dependence on bias voltage. The IC consists of a receiver (a preamplifier, an automatic gain control (AGC) amplifier, a phase-locked loop (PLL), and a D-type flip-flop (D-F/F)), and a 1:16 demultiplexer (DMUX). An input offset control circuit is included in the AGC amplifier for wide dynamic range. Trench isolation and silicon-on-insulator (SOI) technologies are introduced to reduce crosstalk between the amplifiers and the PLL. Power consumptions are 0.6 W at -5.2 V for the analog part and 0.45 W at -3.3 V for the digital part, which does not include the ECL output buffers.