Group4 Labs has developed and made commercially available for the first time, a composite semiconductor wafer that comprises of heteroepitaxial Gallium Nitride (GaN) compound semiconductor films atomically attached to specially treated free-standing polycrystalline chemical vapor deposited (CVD) diamond substrates.
The company's team of scientists and engineers has invented two key materials science technologies that have led to the breakthrough represented in the GaN-on-Diamond wafers introduced here: Firstly, the team has invented physio-chemical surface-science technologies to render coarse poly-crystalline CVD diamond substrates easily receptive to single-crystal epitaxial semiconductor films. Secondly, the team has invented an approach to atomically attach single-crystal heteroepitaxial semiconductor compounds to the specially treated (normally hostile) CVD diamond substrates.
This GaN-on-Diamond wafer system enables extremely efficient heat extraction from the heat-generating heteroepitaxial device layers since the heating layers reside fractions of one nanometer from the diamond – nature's most perfect thermal conductor. The GaN-on-Diamond epitaxial wafer system has been designed for customers that manufacture very high-power, high-temperature, and high-frequency transistor-based circuits. Such circuits are typically found in Power Amplifiers, Microwave and Millimeter wafer circuits all of which may be deployed in cellular base stations, radar communications equipment, weather and communications satellite equipment, etc.
Thermal profile of GaN transistors on SiC substrates (left),
and Diamond substrates (right)
Figure 1. At an ambient temperature of 80°C, 100 W/cm GaN-on-Diamond transistor arrays operate nominally whereas other types of GaN transistors (e.g. GaN-on-SiC, GaN-on-Sapphire) require substantial heat extraction mechanisms to function. This assumes a separation of 10 µm between adjacent transistors. (Details in Simulations & Modeling*)
The company has estimated, proven or conjectured the theoretical concepts that underlie GaN-on-Diamond materials. The reader may refer to the following documents for further technical information.
Dependence of a transistor-array’s packing (power) density on device (junction) temperature
Figure 2. At under 150°C, 100 W/cm GaN-on-Diamond transistor arrays can be packed hundreds of times more densely on a single wafer than GaN-on-SiC transistor arrays. (Details in Simulations & Modeling*, and Power density & thermal simulations*)
Dependency of a transistor’s temperature
on transistor-transistor separation
Figure 3. At 80°C for example, 100 W/cm GaN-on-Diamond transistor arrays can be packed nearly 100 times more densely in a package than GaN-on-SiC transistor arrays. (Details in Simulations & Modeling*)
Technical talks and publications
- Analysis of GaN before- and after-diamond*, published in the 2008 proceedings of the Advanced Technology Workshop on Advanced Substrates and Next Generation Semiconductors. The Workshop is part of the IMAPS (International Microelectronics and Packaging Society). Meeting is held at Linthicum Heights, MD 21090, April 30–May 1, 2008.
- More process-able GaN-on-Diamond wafers*, published in Conference Digest of Papers; CS ManTech Conference, 2008. Meeting is held in Chicago, IL, April 14-17, 2008.
- Cornell demo of 3-W/mm FET-on-Diamond* (PowerPoint version: Group4 models practical GaN-on-Diamond simulations**), published by Cornell University Professor Lester F. Eastman in IEEE Electron Device Letters, 2007.
- Industry demos GaN-on-Diamond FETs*, published by industrial partners at Devices Research Conference, University of Notre Dame, South Bend, Indiana, Jun. 18-20, 2007.
- Cornell: GaN-on-Diamond vs. GaN–on-SiC*, published by Cornell University Professor Lester F. Eastman at WOCSDICE 2007, Venice, Italy, May 20-23, 2007.
- GaN HEMT-on-Diamond Substrates for X-Band applications*, published in Conference Digest of Papers, CS ManTech Conference, 2007.
- The 1st GaN-on-Diamond transistor by Air Force and EMCORE*, published in CSICS symposium proceedings, San Antonio, TX, Nov. 2006.
- The technology of GaN-on-Diamond**
Keys Conference, San Antonio, TX, Nov. 2006.
- GaN-on-Diamond: Why… & How…**
DARPA Threads Workshop, Santa Barbara, CA, Nov. 2006.
* PDF downloads
** PPT downloads
View products
Buy
products >
|
