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

Bilousov, Oleksandr V.; Carvajal, Joan J.; Drouin, Dominique; Vilalta, A.; Ruterana, P.; Pujol, M. C.; Mateos, X.; Diaz, Francesc; Aguilo, Magdalena; O'Dwyer, Colm

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

Files

ECS223_Toronto_2012_GaN_rev.pdf(592.91 KB)

Accepted version

Date

2013-04

Authors

Bilousov, Oleksandr V.

Carvajal, Joan J.

Drouin, Dominique

Vilalta, A.

Ruterana, P.

Pujol, M. C.

Mateos, X.

Diaz, Francesc

Aguilo, Magdalena

O'Dwyer, Colm

Publisher

Electrochemical Society

Published Version

10.1149/05302.0017ecst

Abstract

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.

Keywords

Gallium nitrade , Chemical vapor deposition , Energy gap , Gallium alloys , Metals , Phase interfaces , Semiconductor materials , Vapors

Citation

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