Plasma-induced damage to n-type GaN

Abstract

High-density plasma-induced etch damage of InGaN/GaN multiple quantum well light-emitting diodesThe effects of plasma etching on 1/f noise and photoluminescence ͑PL͒ characteristics of n-GaN have been investigated. A reduction of 1/f noise was observed after plasma exposure, a result of enhanced passivation of the reactive surface. This is attributed to the removal of carbon and the creation of a Ga-rich surface by the etching process. Nevertheless, the formation of nonradiative recombination centers impaired the PL intensity. Reconstruction of a stoichiometric surface was achieved by annealing. This induced the incorporation of carbon into GaN, deteriorating the PL performance further, but it could be restored by a chemical treatment of 10:1 HF:H 2 O.

Low resistivity contacts to p‐type GaN by plasma treatment

“…2. The binding energy of the Ga 3d core level for the as-grown sample centres at 19 eV, characteristic of Ga-N bonding in GaN [8]. A 0.3 eV shift towards lower binding energy is observed from the sample treated at -75 V. This corresponds to a shift of the surface Fermi level 0.3 eV closer to the valence band maximum (VBM).…”

Effects of surface plasma treatment on n-GaN ohmic contact formation

“…One of the approaches to lower contact resistance for n-type GaN is the use of plasma surface treatment prior to metallization [4][5][6][7][8]. High-temperature annealing and plasma treatment have been shown to lead to N 2 outgassing from the GaN surface, possibly resulting in the formation of N-vacancies (V N ) [5,7,[9][10][11][12]. Plasma treatment is also believed to remove contaminant particles from the GaN surface and is able to induce a limited etch damage for enhanced interaction with the metal species.…”

Reliability study on micro‐structured InGaN light‐emitting diodes

“…In a µLED structure, the MQW active layers are disrupted at the peripheries of individual µLED elements. The exposed sidewall surfaces are highly defective due to the exposure of dangling bonds during plasma etching, whereby the incidence of high energy ions leaves behind crystal damage in the surface regions [5]. Such defects trap carriers and induces carrier scattering, resulting in a higher static resistance and reduced carrier mobility [6].…”