Etching Characteristics of ZnO and Al-Doped ZnO in Inductively Coupled Cl₂/CH₄/H₂/Ar and BCl₃/CH₄/H₂/Ar Plasmas

Abstract

ZnO and Al-doped ZnO (AZO) were etched in Cl 2 /CH 4 /H 2 /Ar (Cl 2-based) and BCl 3 /CH 4 /H 2 /Ar (BCl 3-based), inductively coupled plasmas (ICPs) and their etching characteristics were compared by varying the Cl 2 =ðCl 2 þ CH 4 Þ and BCl 3 =ðBCl 3 þ CH 4 Þ flow ratios, top electrode power and dc self-bias voltage (V dc). The etch rates of both ZnO and AZO layers were higher in the Cl 2-based chemistry than in the BCl 3-based chemistry. The AZO and ZnO etch rates were increased and decreased, respectively, with increasing Cl 2 or BCl 3 flow ratio. Optical emission measurements of the radical species in the plasma and surface binding states by optical emission spectroscopy (OES) and X-ray photoelectron spectroscopy (XPS), respectively, indicated that, with increasing Cl 2 or BCl 3 flow ratio; the effective removal of Al in the AZO enhanced the AZO etch rate, whereas the reduced removal of Zn by the Zn(CH x) y products reduced the ZnO etch rate.

Effects of hydrogen ion irradiation on zinc oxide etching

“…Hydrocarbon or similar gases such as methane (CH 4 ) and methanol (CH 3 OH) are indeed favorable choices for RIE of ZnO because of their noncorrosive chemistry and reasonably high etching rates. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] A better understanding of etching reaction mechanisms of ZnO in RIE processes based on such gases is expected to facilitate the development of highly controlled submicron-and nanoscale etching processes of ZnO.…”

Mass-selected ion beam study on etching characteristics of ZnO by methane-based plasma

“…RIE of ZnO has been investigated using various gas plasmas. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Relatively high etching rates can be obtained with halide-gas-based plasmas, but halide-based plasma etching of ZnO has several disadvantages, including the production of etch residues. 19) With methane-based plasmas, on the other hand, etching of ZnO has been achieved with only small amounts of etch residues.…”

Etching characteristics of TaN thin film using an inductively coupled plasma

“…Increasing the RF power increased the number of reactive radicals and ion current density in the BCl 3 /N 2 plasma [19], which contributed to the increase in the etch rate of the TaN thin film. It is thought that the etch rate of the TaN thin film was affected by the RF power [20][21][22]. Fig.…”

“…bias voltage increased up to −250 V. This is explained by the fact that etching of the TaN thin film was affected by the physical action induced by the electric field. And this physical action, ion bombardment by the electric field, is absolutely needed for the etching process of the TaN thin film in the BCl 3 /N 2 plasma[20][21][22][23][24].…”