Renesas Electronics Announces New SiGe:C Heterojunction Bipolar Transistor with the Industry's Top Level of Low-Noise Performance for Wireless LANs and Similar Applications

The new SiGe:C HBT is a transistor that amplifies a weak microwave signal received wirelessly to an appropriate level and achieves a noise figure of 0.75 decibel (dB), which is the industry's top level for the 5.8 gigahertz (GHz) band used by wireless LANs and other applications. The fact that it amplifies with such low noise means that it can increase communication sensitivity in end products. Since it can reduce signal transmission errors, it can achieve operating power consumption as low as one-quarter of those of Renesas' existing products with equivalent performance.

Renesas sells transistors and ICs for microwave amplifier applications, provides solutions for wireless LANs, consumer cordless phones for the home, terrestrial digital TV broadcast tuners, and equipment that includes GPS functionality, and has earned the industry's top market share (Renesas' estimate) for microwave application transistors. Within this context, Renesas has developed a new process technology that uses SiGe:C materials to respond to market needs for even lower noise and to provide solutions for the 12 GHz and higher frequencies used in satellite broadcasting. Based on this process, Renesas has developed and is now releasing the NESG7030M04 SiGe:C HBT device that achieves both the industry's highest level of low-noise performance as well as stable performance over a wide frequency range from a few MHz to the 14 GHz band.

(1) The industry's highest level of low-noise performance in the 5.8 GHz band
By applying this newly-developed SiGe:C process (Note 3), Renesas 5.8 GHz band SiGe:C HBT and SiGe HBT devices achieve the industry's lowest noise figure of 0.75 dB. This is an improvement of 0.35 dB over earlier Renesas SiGe HBT devices. Also, this device achieves a gain at the minimum noise figure of 14.0 dB. This allows communication sensitivity to be increased or signal transmission errors to be reduced and the new device can achieve equivalent performance to earlier Renesas products at 1/4 the power consumption.

(2) Increased withstand voltage for stable operation over a wide bandwidth
In earlier silicon-based heterojunction bipolar transistors, it was not possible to avoid a reduction in the collector-emitter withstand voltage in exchange for reducing noise, and this limited the range of applications these devices could be used in. In this new product, Renesas optimized the collector-base profile, making it possible to guarantee a withstand voltage rating of 4.3 V. This increases the range of supply voltages that can be used and makes stable operation possible over a wide frequency range, from a few MHz to the 14 GHz band. This makes it possible to use this device in a wider range of application. For example, it can support all ISM band (Note 4) applications, including smart grid, smart meter, and home area network (HAN) applications.

Furthermore, since this transistor was developed for microwave applications, Renesas provides it in an industry standard 4-pin thin-form mini-molded package (Renesas package name: M04 package). Thus this product can contribute to a reduction in manufacturing steps in user end products, for example simplifying the mounting evaluation process due to the track record of existing packages, or using an existing circuit board pattern and modifying surrounding circuits slightly

At the same time as expanding their product line of bipolar transistors with the industry's highest level of low-noise performance by taking advantage of this new process, Renesas is also committed to deploying this new process to the development of microwave ICs and providing further solutions in this area to respond to market needs.

(Note 1) This is an fT = 100 GHz process that combines the Renesas SiGe:C heterojunction bipolar transistor and a 0.15 µm CMOS process and is optimized for microwave IC applications.
BiCMOS: Bipolar complementary metal oxide semiconductor. This is a process that can manufacture mixed bipolar and CMOS devices. It can be used to manufacture microwave application ICs by combining the bipolar technology optimal for high-frequency circuits and CMOS technology that supports high-density low-power circuit design.

Renesas positions this process as the next generation process following the Renesas process, which Renesas has been using up to now. Renesas is committed to continuing their process development efforts.

(Note 2) The silicon-germanium: carbon heterojunction bipolar transistor (SiGe:C HBT) is a transistor optimal for microwave applications implemented by combining a process technology that improves device performance by adding small amounts of germanium and carbon to the silicon transistor base with a process that forms electron paths that allow high-speed transport at high density in the semiconductor using heterojunctions.

(Note 3) Application of the SiGe:C process to this new product
To aim for lower noise in the microwave range, Renesas worked to increase electron speed in the base and reduce the base resistance by using a newly-developed SiGe:C process with optimized selective epitaxial growth crystal growth technology that reduces the base resistance of the transistor (which has an emitter, base, and collector structure) by about 60% and by optimizing their 0.15 µm fine fabrication technology.

Epitaxial growth: a process technology that limits crystal growth in the semiconductor to just the section that becomes the transistor's base layer.

(Note 4) ISM: Industrial scientific and medical band. The ISM band is a band of frequencies allocated for general-purpose use by the industrial, scientific, and medical fields. Wireless systems that use this band include wireless LANs, Bluetooth, amateur radio, DSRC, various types of radar, cordless telephones, ZigBee, and other applications.

Pricing and Availability

Samples of Renesas' new SiGe:C HBT are available now, priced at US$0.45 per unit. Mass production is scheduled to start in November 2011 starting from 1,000,000 units per month, and is expected to reach 50,000,000 units per month together with the company's existing SiGe HBT products.