Metal catalyzed porous n-type GaN layers: low resistivity ohmic contacting and single-step MgO/GaN diode formation

Thumbnail Image
Bilousov, Oleksandr V.
Carvajal, Joan J.
Drouin, Dominique
Vilalta, A.
Ruterana, P.
Pujol, M. C.
Mateos, X.
Diaz, Francesc
Aguilo, Magdalena
O'Dwyer, Colm
Journal Title
Journal ISSN
Volume Title
Electrochemical Society
Published Version
Research Projects
Organizational Units
Journal Issue
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
Link to publisher’s version
© 2013 ECS - The Electrochemical Society