Eiji Ohue

A 0.2-/spl mu/m 180-GHz-f/sub max/ 6.7-ps-ECL SOI/HRS self aligned SEG SiGe HBT/CMOS technology for microwave and high-speed digital applications

A technology for combining 0.2-/spl mu/m self-aligned selective-epitaxial-growth (SEG) SiGe heterojunction bipolar transistors (HBTs) with CMOS transistors and high-quality passive elements has been developed for use in microwave wireless and optical communication systems. The technology has been applied to fabricate devices on a 200-mm SOI wafer based on a high-resistivity substrate (SOI/HRS). The fabrication process is almost completely compatible with the existing 0.2-/spl mu/m bipolar-CMOS process because of the essential similarity of the two processes. SiGe HBTs with shallow-trench isolations (STIs) and deep-trench isolations (DTIs) and Ti-salicide electrodes exhibited high-frequency and high-speed capabilities with an f/sub max/ of 180 GHz and an ECL-gate delay of 6.7 ps, along with good controllability and reliability and high yield. A high-breakdown-voltage HBT that could produce large output swings for the interface circuit was successfully added. CMOS devices (with gate lengths of 0.25 /spl mu/m for nMOS and 0.3 /spl mu/m for pMOS) exhibited excellent subthreshold slopes. Poly-Si resistors with a quasi-layer-by-layer structure had a low temperature coefficient. Varactors were constructed from the collector-base junctions of the SiGe HBTs. MIM capacitors were formed between the first and second metal layers by using plasma SiO/sub 2/ as an insulator. High-Q octagonal spiral inductors were fabricated by using a 3-/spl mu/m thick fourth metal layer.

130-GHz f/sub T/ SiGe HBT technology

A real emitter/base heterojunction was formed with the optimization of the vertical profile of the transistor, and good crystallinity of SiGe was achieved by using a UHV/CVD system with high-pressure H/sub 2/ precleaning of the substrate. As a result, a record cutoff frequency up to 130 GHz and the current gain up to 29,000 were obtained with a graded and uniform Ge profiles, respectively.

A selective-epitaxial SiGe HBT with SMI electrodes featuring 9.3-ps ECL-gate delay

A selective-epitaxial SiGe base heterojunction bipolar transistor (HBT) with self-aligned stacked metal/IDP (SMI) electrodes is proposed. The SiGe-base structure, self-aligned to the 0.1-/spl mu/m-wide emitter, effectively reduces collector capacitance and SMI electrodes provide low parasitic resistances. A BPSG/SiO/sub 2/-refilled trench was introduced to reduce the substrate capacitance. A 9.3-ps delay time in a differential ECL ring oscillator was achieved.

Design of a 32.7-GHz bandwidth AGC amplifier IC with wide dynamic range implemented in SiGe HBT

A wide-bandwidth automatic gain control (AGC) amplifier IC was developed using a self-aligned selective-epitaxial SiGe heterojunction bipolar transistor (HBT). A transimpedance load circuit was used, and its damping factor was optimized to achieve a wide bandwidth of 32.7 GHz. Capacitor peaking was introduced to the second variable-gain amplifier in order to obtain a wide gain dynamic range of 19 dB. The amplifier IC has a noise figure of 18 dB and an eye pattern at 25 Gb/s.

45 GHz transimpedance 32 dB limiting amplifier and 40 Gb/s 1:4 high-sensitivity demultiplexer with decision circuit using SiGe HBTs for 40 Gb/s optical receiver

A preamplifier with 45 GHz bandwidth and 50.2 dB/spl Omega/ transimpedance gain, a limiting amplifier with 32 dB gain and 49 GHz bandwidth, and a 40 Gb/s 1:4 high-sensitivity demultiplexer (HS-DEMUX) combined with a decision circuit are for use in a 40 Gb/s optical receiver. The bandwidth in the preamplifier and the maximum gain at 40 GHz in the limiting amplifier are the best reported for any semiconductor technology. The 1:4 HS-DEMUX uses bit-rotation for byte-synchronization.

82 GHz dynamic frequency divider in 5.5 ps ECL SiGe HBTs

A dynamic frequency divider with 82.4 GHz maximum operating frequency, the fastest reported in any semiconductor technology, and a static frequency divider with 60 GHz maximum operating frequency, the fastest reported in Si, are intended for future millimeter-wave systems. These frequency dividers are fabricated in self-aligned selective-epitaxial-growth (SEG) SiGe heterojunction bipolar transistors (HBTs). These SiGe HBTs provide a 122 GHz cutoff frequency, a 163 GHz maximum oscillation frequency, and 5.5 ps ECL gate delay, the fastest reported in Si.

Ultra-low-power and high-speed SiGe base bipolar transistors for wireless telecommunication systems

Ultra-low-power and high-speed SiGe base bipolar transistors that can be used in RF sections of multi-GHz telecommunication systems have been developed. The SiGe base and a poly-Si/SiGe base-contact were formed by selective growth in a self-aligned manner. The transistors have a very small base-collector capacitance (below 1 fF for an emitter area of 0.2/spl times/0.7 /spl mu/m) and exhibit a high maximum oscillation frequency (30-70 GHz) at low current (5-100 /spl mu/A). The power-delay product of an ECL ring oscillator is only 5.1 fJ/gate for a 250-mV voltage swing. The maximum toggle frequency of a one-eighth static divider is 4.7 GHz at a switching current of 68 /spl mu/A/FF.

A 7.7-ps CML using selective-epitaxial SiGe HBTs

The fastest CML gate delay to date (7.7 ps) was achieved. This CML gate uses a fully-self-aligned SiGe-base HBT (with a 92 GHz cutoff frequency and a 108 GHz maximum oscillation frequency) with a selectively-implanted collector through the base.

A 0.2-/spl mu/m self-aligned SiGe HBT featuring 107-GHz f/sub max/ and 6.7-ps ECL

A 0.2-/spl mu/m self-aligned selective-epitaxial-growth (SEG) SiGe heterojunction bipolar transistor (HBT), with shallow-trench and dual-deep-trench isolations and Ti-salicide electrodes, was developed. The process, except the SEG, is almost completely compatible with well-established BiCMOS technology. The SiGe HBTs exhibited a peak maximum oscillation frequency of 107 GHz and an ECL gate delay time of 6.7 ps. Four-level interconnects, including MIM-capacitors and high-Q inductors, were formed by chemical mechanical polishing.

Ultra-high-speed scaled-down self-aligned SEG SiGe HBTs

A self-aligned selective-epitaxial-growth (SEG) SiGe HBT with a funnel-shape emitter electrode, which is structurally optimized for an emitter being scaled-down towards 100 nm, was developed. This SiGe HBT has an ECL gate delay of 4.9 ps, and implemented in an ultra-high-speed static frequency divider, produces a maximum operating frequency of 81 GHz.