Metal catalyzed porous n-type GaN layers: low resistivity ohmic contacting and single-step MgO/GaN diode formation
Bilousov, Oleksandr V.
Carvajal, Joan J.
Pujol, M. C.
Porous GaN crystals have been successfully grown and electrically contacted simultaneously on Pt- and Au-coated silicon substrates as porous crystals and as porous layers. By the direct reaction of metallic Ga and NH3 gas through chemical vapor deposition, intermetallic metal-Ga alloys form at the GaN-metal interface, allowing vapoursolid- solid seeding and subsequent growth of porous GaN. Currentvoltage and capacitance-voltage measurements confirm that the intermetallic seed layers prevent interface oxidation and give a highquality reduced workfunction contact that allows exceptionally low contact resistivity. Additionally, the simultaneous formation of a lower workfunction intermetallic permits ohmic electron transport to n-type GaN grown using high workfunction metals that best catalyze the formation of porous GaN layers and may be employed to seed and ohmically contact a range of III-N compounds and alloys for broadband absorption and emission. Additionally, we show how a porous GaN rectifying diode can be formed by oxidatively crystallizing Mg typically employed for p-doping GaN, as a layer formed under porous structure resulting in a high-k polycrystalline MgO dielectric.
Gallium nitrade , Chemical vapor deposition , Energy gap , Gallium alloys , Metals , Phase interfaces , Semiconductor materials , Vapors
Bilousov, O. V., Carvajal, J. J., Drouin, D., Vilalta, A., Ruterana, P., Pujol, M. C., Mateos, X., Díaz, F., Aguiló, M. and O'Dwyer, C. (2013) 'Metal Catalyzed Porous n-type GaN Layers: Low Resistivity Ohmic Contacting and Single-Step MgO/GaN Diode Formation', ECS Transactions, 53(2), pp. 17-27. doi: 10.1149/05302.0017ecst
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