Selective etching of GaAs and Al0.30Ga0.70As with citric acid/hydrogen peroxide solutions

1990 ◽  
Vol 8 (5) ◽  
pp. 1122 ◽  
Author(s):  
C. Juang
Keyword(s):  
Hydrogen Peroxide ◽  
Citric Acid ◽  
Selective Etching

Research on Effects of Slurry Additives in Cu CMP for ULSI Manufacturing

2006 ◽  
Vol 304-305 ◽  
pp. 350-354 ◽  
Author(s):  
X.J. Li ◽  
Dong Ming Guo ◽  
R.K. Ren ◽  
Zhu Ji Jin
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Electrochemical Impedance Spectroscopy ◽  
Citric Acid ◽  
Chemical Mechanical Polishing ◽  
Electrochemical Impedance ◽  
Etching Rate ◽  
Complexing Agent ◽  
Cu Cmp ◽  
Static Etching

In this paper, in order to analyze the oxidation, dissolution and corrosive inhibition effects of additives in the slurry for copper Chemical-mechanical polishing(CMP), the slurry(pH5) with the peroxide as an oxidant, the citric acid as a complexing agent and the benzotriazole(BTA) as an inhibitor is studied. The static etching rate and polishing rate of the Cu-H2O2-Citric acid-BTA slurry are measured. The electrochemical behavior involved in the dissolution and corrosive inhibition of copper in the solutions containing additives is investigated by the electrochemical impedance spectroscopy (EIS) studies. The surface roughness is measured using ZYGO 3-D surface profiler. It is observed that when the slurry is with only 5wt% peroxide existing, copper is stable and slight etching rate on the copper is produced, and the etching rate is only 8.7nm/min. When 0.6wt% citric acid presents after adding 5wt% hydrogen peroxide, the etching rate will increase by 5.3 times, with a blue complexing product emerging. When the inhibitor BTA is added, the corrosion will be effectively restrained. From the EIS results, the impedance of copper in 5wt% peroxide solution which is in passivation can be greatly decreased by adding the citric acid as a complexing reagent. And the impedance of copper in the solution containing peroxide and citric acid can be increased by the addition of BTA. The surface roughness of the wafer polished with the slurry of 5wt% peroxide+0.6wt% citric acid+0.12wt% BTA slurry is Ra 4.7 Å.

Selective etching of GaAs grown over AlAs etch-stop layer in buffered citric acid/H 2 O 2 solution

2017 ◽  
Vol 63 ◽  
pp. 52-57 ◽  
Author(s):  
A. Kuźmicz ◽  
K. Chmielewski ◽  
O. Serebrennikova ◽  
J. Muszalski
Keyword(s):  
Citric Acid ◽  
Selective Etching ◽  
Etch Stop ◽  
Etch Stop Layer

Effect of complexing agents on desulphurization and deashing of coal by H2O2/H2SO4 leaching

2018 ◽  
Vol 29 (7) ◽  
pp. 1142-1154
Author(s):  
Hafiza Sana ◽  
Rizwan Haider ◽  
Muhammad Usman Rahim ◽  
Shahid Munir
Keyword(s):  
Hydrogen Peroxide ◽  
Citric Acid ◽  
Phosphoric Acid ◽  
Removal Efficiency ◽  
Coal Sample ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Chemical Leaching ◽  
Optimized Conditions

The present study was aimed at investigating the effect of the addition of complexing agents on the removal efficiency of sulphur and ash contents during chemical leaching by acidified hydrogen peroxide. Representative coal sample from Lakhra was subjected to chemical leaching under various conditions of the parameters including time (60 and 120 min), temperature (25 and 50°C), complexing agents (citric acid and phosphoric acid) and the concentration of complexing agents (100 and 1000 ppm). The addition of complexing agents, i.e. citric acid and phosphoric acid imparted significant effects on improving the removal efficiency of sulphur and ash contents. Under optimized conditions, it was found out that the addition of citric acid improved the removal efficiency for sulphur from 63.88 to 83.47% and from 33.12 to 66.25% for ash. In case of phosphoric acid, the removal in sulphur and ash contents was increased from 63.77 to 80.77% and from 33.12 to 59.18%, respectively. Apparently, citric acid happened to be the most effective complexing agent, as compared to phosphoric acid. These results warrant subsequent detailed studies for further optimization of the process, including the use of some other complexing agents, as well.

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