Cl[sub 2]-Based Dry Etching of GaN and InGaN Using Inductively Coupled Plasma The Effects of Gas Additives

Abstract

The effects of added H 2 , Ar, and CH 4 gases on the etch characteristics of GaN and InGaN were studied using an inductively coupled Cl 2 -based plasma. Each added gas had a unique effect on the etch rate, anisotropy, surface roughness, and sidewall morphology. The most anisotropic etch profile was obtained using Cl 2 , but the etched surface showed the roughest morphology and was covered with etch residues, the origins of which were the micromasking of the sputtered dielectric. When H 2 gas was added to the Cl 2 plasma, the etch residues were removed and the surface roughness was decreased, even though the etch rate was slightly decreased. The etch rate of GaN by Cl 2 /H 2 /Ar plasmas was saturated above an Ar flow rate of 16 sccm and the surface roughness of the etched GaN was lower, compared with Cl 2 /H 2 plasmas at low source power. Finally, it was found that the In compound was etched as a result of reaction with CH 4 .

Formation of large-area GaN nanostructures with controlled geometry and morphology using top-down fabrication scheme

“…The increase in etch rate due to Ar addition has been attributed to the increase in ion density due to Penning ionization. 15 Also in Fig. 3, suppression of etch mask erosion is observed with the addition of N 2 compared to pure Cl 2 and Cl 2 /Ar recipes.…”

“…Hahn et al 14 studied the effects of adding He, Ar, and Xe to Cl 2 in ICP plasma and showed that the etch rate was highest for the Cl 2 /He. Lee et al 15 also studied the effects of gas additives such as H 2 , Ar, and CH 4 in Cl 2 -based chemistries for ICP etching of GaN and InGaN. They used rare-gas actinometry to identify the increased concentration of atomic Cl radical when Ar is added to the Cl 2 /H 2 , which resulted in higher etch rates as compared to Cl 2 /H 2 only.…”

Photoluminescence depth‐profiling of lattice‐mismatched InGaN thick film on GaN using inductively coupled plasma etching

“…All samples were cut into 10 × 10 mm square. Cl 2 etching in the inductively coupled plasma system (Plasmalab system100 ) [13] was performed under the conditions of 30 sccm of a Cl 2 flow rate, a 10 mTorr chamber pressure, and 1000 and 50 W of ICP and radio frequency table power (induced dc bias of less than -20 V), which are the optimal condition for the purpose of minimizing parasitic effects by dry etching. The etch rate of In 0.1 Ga 0.9 N and In 0.15 Ga 0.85 N was about 7-8 Å/sec.…”

Doping level-dependent dry-etch damage in n-type GaN

“…During the last decade, a variety of etching methods for the reliable pattern transfer of GaN have been reported, and a dry etching method has proven to be effective for the fabrication of light emitting diodes (LED) and laser diodes [1][2][3]. However, energetic ion bombardment-induced damage, which accompanies the dry etch process can lead to the deterioration of the optical and electrical properties of the semiconductors [4][5][6][7].…”