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1068-C01-08

Investigation of Blistering Phenomena in Hydrogen-Implanted GaN and AlN for Thin Film Layer Transfer Applications R. Singh1, R. Scholz2, S. H. Christiansen2, and U. Goesele2 1 Physics, Indian Institute of Technolgy Delhi, Hauz Khas, New delhi, 110016, India 2 Experimental II, Max Planck Institute of Microstructure Physics, Weinberg 2, Halle, 06120, Germany ABSTRACT High fluence hydrogen implantation-induced blistering phenomena in GaN and AlN have been investigated for potential thin film layer transfer applications. GaN and AlN were implanted with 100 keV H2+ ions with various ion fluences in the range of 5×1016 to 2.5×1017 cm−2. After implantation the samples were annealed at higher temperatures up to 800°C in order to observe the formation of surface blisters. In the case of GaN only those samples that were implanted with a fluence of 1.3×1017 cm−2 or higher showed surface blistering after post-implantation annealing. For AlN the samples those were implanted with a fluence of 1.0×1017 or 1.5×1017 cm−2 displayed surface blistering after post-implantation annealing. Cross-sectional transmission electron microscopy was utilized to observe the microscopic defects that eventually caused surface blistering. Large area microcracks, as revealed in the XTEM images, were clearly observed in the case of both GaN and AlN after post-implantation annealing. A comparison of the hydrogen implantation-induced blistering in GaN and AlN has also been presented. INTRODUCTION Wide bandgap nitride semiconductors such as GaN and AlN have a wide range of applications in the area of optoelectronics as well as high frequency, high power electronic devices [1-3]. These nitrides are mostly grown epitaxially on lattice and thermal mismatched substrates like sapphire, SiC or even on Si due to the fact that free-standing bulk substrates of GaN and AlN are very expensive and are mostly available in small sizes [4-6]. The heteroepitaxial growth of nitride epitaxial layers on foreign substrates leads to the formation of growth-related defects like dislocations, stacking faults, twins etc. that occur to relax the strain. The high density of dislocations in the nitride epitaxial layers grown on hetero-substrates has deleterious effects on the performance and reliability of the devices fabricated utilising these layers. One of the methods to fabricate low-cost and high structural quality substrates, comparable to free-standing substrates of GaN and AlN, for the epitaxial growth of group-III nitrides would be direct wafer bonding and layer transfer of thin GaN films via a high fluence hydrogen implantation and layer splitting upon annealing [7, 8]. The free-standing GaN and AlN substrates can be utilised to transfer multiple layers on other substrates. This process is based upon the agglomeration of hydrogen implantation-induced platelets upon annealing and the subsequent formation of over-pressurized microcracks. For the case of the implanted wafer bonded to a handle wafer, splitting of a thin slice of material parallel to the bonding i