November 1, 2007
Wafers Reach New Maturity
Dear Customers and Development Partners,
We’re approaching the end of our fourth year of operation, and Group4 Labs has had yet another landmark year in terms of product development. Our industry-transformational GaN-on-Diamond wafers are yet closer than ever to mass production.
In recent months, our beta commercial wafer product reached a new level of maturity. The 50-micron thick, 2” GaN FET-on-Diamond epitaxial wafers exhibited an end-to-end GaN attachment yield of nearly 100%. The free-standing wafer-bow measures less than 400-microns on average from batch to batch in the manufacturing line. The wafer-bow measure less than 30-microns when flat-mounted on a quartz handle wafer. Most important about our wafers, there is little batch-to-batch statistical variation in the manufacturing line.
Also recently from our partners, key electronic properties of GaN FET epitaxy were examined before it was attached to diamond (i.e. it still resided on Si), and after it was peeled from Si and attached to diamond. The two epitaxy exhibited indistinguishable electronic properties. Some new defects emerged in the GaN-on-Diamond wafer, but they did not affect the FET epitaxy’s all-important Hall mobility, sheet resistivity, and carrier concentration – indicating that our wafer formation process did not adversely affect the core device properties of the GaN FET epitaxy. Detail results of this study shall be presented by AFRL at the 2008 CS ManTech conference meeting.
Beginning in January 2008, we will ship samples of our 2” GaN FET-on-Diamond epitaxial wafers to customers. The diamond’s thickness, and power-level of the GaN epitaxy have been specifically designed for power amplifiers used in commercial cellular base-stations, WiMax systems, and other commercial RF devices. Thicker and wider area diamond wafers, along with GaN FET epitaxy designed for very high power X-band radar applications shall continue to be under development at Group4 Labs. Also, work will continue in the next year to further customize the wafers for particular customer applications in the X-band radar, and optical display and storage applications.
We continue to be deeply grateful for the generosity of far-sighted development partners and customers in the commercial sector and the U.S. defense community including teams at AFRL. Several SBIR awards have been made to the company in 2007 and this has been invaluable in helping us to unveil the revolutionary new platform of GaN-on-Diamond.
Warm Regards,
Felix Ejeckam
CEO |
