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The Reading Room:
August 2003
Welcome
to the our collection of papers and articles found whilst surfing
the web. Here we provide for your further reading enlightenment and
entertainment diverse types of nitride-related papers and articles
scattered at the four corners of the Internet.
As always we can
vouch for none of them as regards veracity or hyperbole. Some are in
HTML while others require you have an Acrobat reader. Just right
click and choose either 'open in new window' or 'save target as' to
put it on your hard drive for later perusal. Some will not be around
for long as they have a time-limit as a service to authors. Most are
of course copyright so check with the originator before you do
anything serious with them.
Finally, if you have a white paper or
technical / business article you would like to see on this page
please drop us a line. It's a nice way to draw traffic to your
site.
New: See the revamped Nitronex
website for some choice nitride-related papers such as the one
by W Nagy, et al., entitled 'Linearity characteristics of microwave
power GaN HEMTs' This from IEEE Transactions on Microwave Theory and
Techniques, 51(2), 660-664.
Also
for an overview on LEDs applied to illumination see the Popular
Mechanics mag article c/o Lumileds. Or the automotive
applications thereof.
Sony
Accelerates Introduction of First Blu-ray Disc
Recorder
by Masayuki Arai, of Nikkei Electronics, includes a good
description of the new Sony DVD and unusually it has some photos of
the internal mechanism.
Simulations in the Development Process of GaN-based
LEDs and Laser Diodes by Dominik
Eisert and Volker Härle at Osram Opto Semiconductors
GmbH.
Ultraviolet and
Visible Devices Based on III-Nitride
Semiconductors
III-nitride materials have become one of the most interesting
and hot topics of research among the semiconductor community. They
owe this attention to an excellent potential for use in both
electrical and opto devices. The Center for Quantum
Devices Evanston, IL, has played an important role in the
development of III-nitrides, demonstrating world record achievements
in both light emitting and light detecting devices. This research
has been funded by DoD. Some of the most recent and important
achievements are highlighted.
Brighter
Whites, Greens and Blues in Store for LEDs
A new process of growing gallium nitride on an etched
sapphire substrate, called cantilever epitaxy, may help light up the
world with brighter green...
Stress Controlled
MBE-growth of GaN:Mg and GaN:Si
A pdf
of a paper by Y. Kim, et al., of Department of Materials Science and
Mineral Engineering, University of California, Berkeley, it is
demonstrated that the electron Hall mobility in GaN:Si can be
increased with constant electron carrier concentration if large
compressive stress is present.
Gallium
nitride electronic devices for high-power wireless
applications
Ric Borges
asks 'Could semiconductors based on GaN technology be the answer to
tomorrows hardened high-power wireless systems?'
Novel substrates to reduce cost and increase throughput of
blue LED production - a pdf of this
article is downloadable from TDI
Inc.
64x64 matrix-addressable arrays of GaN-based
microLEDs
Download this interesting LEOS paper from the Institute of
Photonics at the University of Strathclyde, Glasgow, Scotland, from
December 2002.
Technology Analysis: Blue LED Manufacturers Ready to
Compete
Nichia and Toyoda Gosei reconciled
their legal differences in September 2002. Now Japanese, Taiwanese
and US manufacturers are competing to develop not only blue LEDs but
also white LEDs.
The new product is mostly targeted for substrate
applications for AlGaN/GaN high electron mobility transistors
(HEMTs). Perfectly lattice matched to GaN-based devices, this low
cost semi-insulating substrate is excellent for a variety of nitride
electronic devices.
High quality GaN substrates are required to
fabricate long-lived, efficient and reliable optoelectronic and
electronic devices. Nitride semiconductors are currently used in a
variety of components such as near UV laser diodes for next
generation DVDs, high brightness LEDs for general lighting and high
power, high frequency transistors for cellular phone base stations
and defense applications.
Bottleneck on the Road to
3G
In Wireless Future Magazine Sandip Patel of
Nitronex explains how better power amplifiers can improve 3G
networks.
WS: http://www.wirelessfuturemagazine.com/3gbottleneck.html
Optimization of
High Mobility GaN by rf-assisted MBE
By B
Heying, et al., Materials Dept., University of California, Santa
Barbara, addresses the issue of significantly lower mobility values
in MBE-grown material due to intrinsic point defects that limit
transport properties. In addition, GaN films grown by MBE typically
have higher dislocation densities than films grown by MOCVD or HVPE,
so dislocation scattering could also contribute to the lower
mobility values measured for MBE-grown material. Here they produce
low dislocation density MBE-GaN films by utilizing MOCVD-grown GaN
templates as substrates.
A
Comparative Study Of GaN Diodes Grown by MBE on Sapphire and
HVPE-GaN /Sapphire Substrates
By
Anand V. Sampath, et al., ECE Department, Boston University, 8. St.
Mary's St. Boston, and Photonics Center, Boston University, reports
on the fabrication and characterization of GaN diodes(Schottky and
p-n junctions) grown by plasma assisted MBE. They observed that
Schottky diodes improve both in reverse as well as forward bias when
deposited on 5 µm thick HVPE n+-GaN/sapphire instead of bare
sapphire substrates.
Broadband Amplifier Design Using SiC
MESFETs
by Dr. Todd W. Nichols, Senior RF
Engineer, Cree Microwave, Inc.
Designing amplifiers to cover
more than one band will reduce both capital equipment and operating
costs for the infrastructure market. Single-ended and balanced
demonstration amplifiers using Cree CRF22010 silicon carbide MESFETs
are presented. These sample amplifiers demonstrate the potential
that wide band-gap semiconductors hold for this market.
WS: http://www.mpdigest.com/Articles/2002/Oct2002/cree/Default.htm
An
overview article of the status of High-volume production of
AllnGaN-based LEDs can be found here.
ITRI shows off Taiwan's first GaN laser go
here.
Well-known itinerant roving reporter Alan Mills is also a
frequent commentator on wide band gaps and other topics, see here
an example of his work in TFR. An excellent overview of the
Intertech 3rd LED Business Conference.
All my own work...
I have over the years written many an article
on nitride semiconductors - as well as several market reports - but
most of these are copyright to Elsevier as they were commissioned
for the magazine I founded, III-Vs Review. One day I will
get around to including a list of all these on this website, for now
I suggest you take a look at Science Direct which has my stuff going
back nearly 10 years.
Violet
diode lasers go continental
It had long
been conjectured that today's gallium nitride (GaN) violet laser
diodes (VLDs) were a compromise. Their very existence is contingent
upon hetero-epitaxial crystal growth, which uses multiple
semiconducting layers deposited on top of a dissimilar material such
as sapphire (Nichia; Japan) or silicon carbide (Cree; Durham, NC).
Researchers believed that homo-epitaxial growth could lead to
improved results, including the production of higher-power lasers at
ultraviolet wavelengths.
Scroll
down to read this article
I wrote a while ago for SPIE's OEMagazine.
And
here is one I wrote for IOPP's OLE Magazine:
Market report: Blue
diodes infiltrate the domestic market
Abstract: "The future is bright for the latest light-emitting
diodes on the market. Blue and white versions have come a long way
in the last two years. Roy Szweda looks at the latest developments
taking place in Europe and around the world."
On the
Aixtron Press Clippings page you can read and download some more
articles etc. For instance there is my article entitled "Compounds
vs silicon for solar cells: less is more" which includes some
reference to nitrides as used to create next-generation solar
cells.
I also write about GaN topics for my editorials in TFR called
'Crystal Gazing. Here is one example: LEDs
to enhance safety at Grand Prix motor races
Finally, see this page for a list
of interesting reading links.
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