Formation of Rough GaN Surface by Hydrogen Plasma Treatment and Its Application to Field Emitter

Abstract

N-type GaN layers doped with Si are grown on sapphire substrates with AlN buffer layers by the metalorganic chemical vapor deposition method. The electron density is 2×1017 cm-3. The GaN surface is treated with hydrogen (H2) plasma produced by supplying microwave power. Etching of GaN with H2 plasma leads to the formation of a roughened GaN surface. An enhancement of the electric field at the roughened surface makes it possible to reduce the average electric field between the anode electrode and the sample surface for electron emission. The turn-on electric field for the electron emission is estimated to be as low as 12.4 V/µm.

Improved field-emission characteristics of GaN by BN coating

“…17,18 Three parts of unevenness labeled as r 1 , r 2 , and r 3 are chosen from the largest in the roughness profile. 2 and 4, the turn-on voltages of which are almost the same.…”

“…17,18 Sample C was a GaN layer coated with BN film as thin as 10 nm. Sample A was an as-grown GaN layer on the sapphire substrate.…”

Etching of GaN by microwave plasma of hydrogen

“…Gallium nitride (GaN) is a wide band-gap (3.4 eV) semiconductor material, which finds applications in highpower and high frequency devices such as power amplifiers, and in optoelectronics for light-emitting diodes (LEDs) and laser diodes. Sapphire (Al 2 O 3 ) and silicon carbide (SiC) are the most commonly used substrates for GaN-based LEDs, which can be used in many fields including green traffic lights, full-color displays and flat-panel room lighting to replace incandescent and fluorescent fixtures [1][2][3][4][5]. The most common and successful technique for the growth of epitaxial GaN films is metalorganic chemical vapor deposition (MOCVD).…”

Field emission characteristics of GaN roughened with H2 plasma

“…7,8 This technique is much easier than fabrication of the GaN pyramids, being applicable to fabrication of field emitters. 7,8 This technique is much easier than fabrication of the GaN pyramids, being applicable to fabrication of field emitters.…”