Updated July 19,
here to go to our main page on microwave semiconductor technologies
here to go to our page on antimonide-based compound semiconductors
here to go to our page on gallium arsenide semiconductors
here to go to our page on gallium nitride semiconductors
here to go to our page on silicon semiconductors for microwaves
New for August 2009! We've
split our page on microwave
semiconductor technologies page into multiple pages.
is like the weird uncle of gallium arsenide. It has some quirks,
including being very brittle, and it costs more than GaAs. But
some of the highest frequencies of operation reported are on
InP, so it will always serve a niche as systems move toward
terahertz. GaAs MHEMT can be tailored to behave almost like
InP, which provides a path toward cheaper production.
This page so far has two topics:
phosphide (InP) HEMT
Indium phosphide HEMT has broken
all of the upper frequency records, on the way to terahertz devices.
However, there are serious drawbacks to this technology, not the
least of which is its high cost. For this reason, InP is more regarded
as a lab curiosity rather than a production process.
The actual semiconductor that
is doing the work in so-called InP is actually InGaAs. Indium phosphide
is merely the substrate that it is grown onto. The reason for this
is that InGaAs shares the same lattice constant with InP, 5.87 angstroms.
substrates are small (3" typical, 4" are available
but remember bigger is not always better when something is brittle).
ER=12.4, close to that of GaAs. A huge drawback of indium phosphide
technology is that InP wafers are extremely brittle compared to
other semiconductors. Try shipping an InP wafer sometime. Silicon
is the least brittle (think Frisbee!), and GaAs is somewhere in
- Extremely low noise
- Useful through W-band
- More expensive than
GaAs due to starting material costs, small size of wafers.
- Extremely fragile.
- Low breakdown voltage
(power is low)
phosphide (InP) HBT
Some people think that InP will
have a second chance to become the most ubiquitous power amplifier
technology for cell phones when new higher power density/lower voltage
lithium ion batteries become available, as suggested in this December
Frequency Electronics article by Michael Gaynor. Here the author
claims that InP has superior low voltage power/efficiency performance
compared to GaAs HBT.
us out with some content on this page!