Development of Epitaxial GaN Films for RF Communications

The primary objective of this SBIR is to develop epitaxial GaN films with threading dislocation density less than 10^6 cm^-2. We propose an innovative approach combining two Pulsed Energy technologies: plasma-energy-controlled Pulsed Laser Deposition (PLD) to deposit high quality epitaxial GaN films, and in situ Pulsed Energy Annealing to decrease the dislocation density ( to < 10^6 cm-2). Unlike low energetic techniques (such as MBE or CVD), PLD's energetic range of pulsed plasma can be controlled with process parameters, resulting in a wide range of plasma energetic for film deposition. Recently, Neocera fabricated high quality epitaxial GaN films using the plasma-energy-controlled PLD process, resulting in strong photoluminescent emission at room temperature. This approach is further extended in this Phase I, with an in-situ "Pulsed" Energy Annealing, to greatly improve the film crystallinity. The pulsed laser or pulsed electron beam, with 20-50 ns pulse width and high power density (~10^8W/cm^2), induces melting and a rapid epitaxial formation in ~100 nanoseconds, anneling out dislocations. This unique combination of two pulsed energy technologies is expected to provide the most advanced deposition process for epitaxial GaN films with low dislocation density.