GaN growth on silicon based substrates using pulsed electron beam deposition (PED) process

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GaN growth on silicon based substrates using pulsed electron beam deposition (PED) process Nazmul Arefin1, Matthew H. Kane2,3, Preston R. Larson4, Vince R. Whiteside5, Khalid Hossain6, Brittany N. Pritchett7, Matthew B. Johnson5 and Patrick J. McCann1 1

School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019 Marine Engineering Technology, Texas A&M University at Galveston, Galveston, TX 77573 3 Materials Science and Engineering, Texas A&M University, College Station, TX 77843 4 Samuel Roberts Noble Microscopy Laboratory, Norman, OK 73019 5 Dept. of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 6 Amethyst Research Inc., Ardmore, OK 73401 7 Mewbourne College of Earth and Energy, University of Oklahoma, Norman, OK 73019 2

ABSTRACT Growth of GaN on Si(111) and Ge coated Si(111) using pulsed electron beam deposition (PED) process is reported. GaN was deposited on Si(111) and Ge/Si(111) at 600°C in an N2 environment without any surface pre-treatment such as pre-nitridation. X-ray diffraction confirmed that c-plane oriented GaN was grown. Photoluminescence showed near-band-edge emission, the intensity of which was improved with hydrogen passivation. Electrical characterization showed n-type conductivity with room temperature electron mobilities in the range of 300 cm2/V-sec. INTRODUCTION Gallium nitride (GaN) is considered a promising material for solid state lighting [1], laser diode [2], photodetector [3], and power electronic device applications [4][5][6][7]. GaN is grown mostly on sapphire, 6H-SiC, and bulk GaN substrates. Future opportunities are associated with GaN growth on silicon substrates due to the significant reduction in manufacturing costs and the prospects for monolithic integration of III-nitride devices with existing silicon device technologies [8] that are possible. For monolithic integration of nitride devices with silicon devices, it is required to grow GaN at low temperatures to preserve previously fabricated silicon devices. Existing commercial MOCVD [9], and MBE [10] processes involve high growth temperatures (at least 800oC), too high for modern silicon devices to withstand. Thus, it is desirable to grow GaN at low temperatures on silicon. Pulsed laser deposition (PLD) processes have been used for the last couple of decades [11] [12] for III-nitride growth. In PLD, the material ablation process is critically dependent on the optical absorption co-efficient of the target material. For most of the solid state target materials, this range is on the order of microns. In the case of III-nitrides, especially AlN (Eg = 6.2 eV), the photon energy of a Kr-F excimer laser (248 nm, 5.01 eV) is too low for good laser/material interaction. In addition, the generated plasma interacts with the incoming laser beam, consuming a big portion of energy from the laser beam. On the other hand, in pulsed electron deposition (PED), material ablation is done with the bombarding of high energy electrons, through a channel spark discharge, on the target creating a high powe