We’ve Got the Power
Trying to mute the old joke that compound semiconductors are the technology of the future and always will be, Dr. Vu Ho recently attended the 2007 International Conference on Compound Semiconductor Manufacturing Technology. The III-V compounds and related materials such as GaAs, GaN and InP have for years been a mainstay of advanced platforms in military and aerospace applications. However, they have not penetrated deeply into the high volume consumer segment that gets executives and investors salivating.
The higher performance offered by the “un-silicon” materials have been well known for many years. Higher carrier mobilities and semi-insulating substrates enable transistors and circuits to operate at higher frequencies and with lower losses (see more details here). For many years, the competition for maximum operating frequencies - f_T and f_MAX - put III-V’s well ahead and kept silicon devices out of the running. In the lucrative cell phone portion of the radio frequency market, compound devices established and maintained a foothold. Those components are all related to the RF front-end. Duplexer filters, switches, output power amplifiers, and receiver amplifiers (LNA’s) were all once III-V based. The first erosion of this share was still a compound, but still silicon-based, as silicon-germanium - SiGe - grabbed a piece of the power amplifier market.
Unfortunately for the III-V community, the huge momentum and power of the silicon world continued to push into this space. In the quest for becoming all-digital, today even low-power stages of the RF path are in digital CMOS. There is even an RF switch in Si - albeit on sapphire. In fact, aggressive scaling CMOS transistor dimensions has driven the speed performance to near III-V levels with all competitors reaching hundreds of gigahertz.
Despite the switching speed, transistor density, and relative ease of integrating many functions in one technology platform, CMOS may not win out. Dr. Ho points out that the breakdown voltage and power handling limitations of silicon devices (including SiGe) will limit their march to higher operating frequencies. According to Dr. Ho, the future of III-V devices looks bright.
Power up.
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SemiSerious » iPhone Sends Out S-O-S to the World said,
July 4, 2007 at 4:29 pm
[…] Peregrine’s UltraCMOS device is very interesting. The iPhone is the first consumer product we have pulled one out of. Peregrine’s technology is the only silicon-based circuit for this application. Its competitors are complex III-V and derivative compounds patterned as p-HEMTs and other such beasts. (Check my last post for some background on III-V’s.) […]