GaN substrates for Superior GaN based Devices

"There is a need for a cost-effective technology for producing III-nitride substrates for fabrication of high efficiency and high power radar transmit/receive modules, as well as opto-electronic devices. The problems with the current technology offabricating III-nitride based devices on thin films grown on foreign substrates, such as sapphire or SiC, are the plethora of defects associated with the lattice and thermal mismatch between substrate and film, which put an upper limit on the performance,efficiency and stability of these devices. To date, efforts in the developments of GaN substrates by solution techniques, sublimation-recondensation methods, and deposition of thick GaN films by the Hydride Vapor Phase Epitaxy (HVPE) method (followed byremoval of the substrate after the growth) have suffered from a combination of residual thermal stresses, poor yield, and high cost.Boston MicroSystems and Boston University propose to develop stress-free GaN substrates by growing thick GaN films using the high growth-rate HVPE method on to novel sacrificial (111) silicon substrates. The low-cost Si(111) substrates are made compliantby an innovative micromachining method. Currently, III-nitride based LEDs and other devices are grown on sapphire or SiC substrates, due to the lack of native substrates. These substrates are expensive and limited to sizes below 100mm. Furthermore, the lattice and thermal mismatch between thefilm and substrates res