Inductively Coupled Plasma Etching of III‐V Nitrides in CH 4 / H 2 / Ar and CH 4 / H 2 / N 2 Chemistries

Chang

Kim

et al. 2001

The dry etching characteristics of ZnO using an inductively couple plasma (ICP) have been investigated, for the first time, as functions of plasma chemistry, radio frequency (rf) table power, and ICP power. The CH 4 /H 2 etchant gases resulted in the highest etch rate of ZnO, suggesting that the etching of Zn in ZnO largely involves a process in which a volatile metallorganic zinc compound, such as Zn(CH 3) y is formed. The etch rate was increased with increasing rf table power, and the highest etch rate of 2000 Å/min was achieved at an rf table power of 200 W (dc bias: Ϫ80 V). As the ICP power was increased, the etch rate also increased, which suggests that the plasma density is also an important factor in this process. Furthermore, it was observed that hydrogen-containing plasma etching enhances the band-edge photoluminescence of the ZnO film.

Section: Resultsmentioning

confidence: 99%

Dry Etching of ZnO Using an Inductively Coupled Plasma

Chang

Kim

et al. 2001

“…At levels of CH 4 in excess of 30%, the etch rate is decreased, which is probably due to the formation of a polymer film which is hydrocarbon in nature. 20 This result suggests that the CH radical intensity is closely related to the etch rate of InGaN and that the In compound is etched by reaction with CH 4 . Therefore, the Cl 2 /CH 4 /H 2 /Ar plasma chemistry is recommended for the etching of In-containing GaN structures.…”

Section: Resultsmentioning

confidence: 93%

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

Chang

et al. 2000

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 .

“…10 These results suggest that the etching mechanism of GaN under these etching conditions is a reactantlimited process, which is very similar to the results in the literature. 15,16 However, the InGaN etch rate was increased with increasing ICP power up to 1000 W, but was saturated above 1000 W of ICP power. Shul et al 6 reported a dry etching of InN using Cl 2 /CH 4 /H 2 /Ar plasma chemistry at high temperatures.…”

Section: Resultsmentioning

confidence: 99%

Dry Etching of GaN/InGaN Multiquantum Wells Using Inductively Coupled Cl[sub 2]/CH[sub 4]/H[sub 2]/Ar Plasma

Kim

Park

2001

Nonselective dry etching of GaN, In 0.12 Ga 0.88 N, and their multiquantum wells ͑MQW͒ was examined using a Cl 2 /CH 4 /H 2 /Ar plasma at room temperature. The etching characteristics were studied as functions of CH 4 concentration, inductively coupled plasma power, and radio frequency table power. Nonselective etching of MQW using a Cl 2 /CH 4 /H 2 /Ar plasma was monitored by means of laser interferometric reflectance. Ga, In, and GaCl as well as CN were observed as group III and group V etch products, respectively, in the optical emission spectrum during plasma etching. By optimizing the CH 4 concentration in the gas mixture, the roughness on the etched surface and the sidewall of the MQW could be substantially reduced. These results indicate that Cl 2 /CH 4 /H 2 /Ar plasma chemistry, combined with a postannealing process for etch-damage recovery, is suitable for the fabrication of optoelectronic devices using GaN, InGaN, and GaN/InGaN MQW.