| AVS 57th International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS2-WeA |
| Session: | Neutral Beam Processing |
| Presenter: | X.Y. Wang, Tohoku University, Japan |
| Authors: | X.Y. Wang, Tohoku University, Japan C.H. Huang, Tohoku University, Japan Y. Ohno, Tohoku University, Japan M. Igarashi, Tohoku University, Japan A. Murayama, Hokkaido University, Japan S. Samukawa, Tohoku University, Japan |
| Correspondent: | Click to Email |
Dry etching is a key technique in top-down process for the fabrication of GaAs/AlGaAs nanometer-scale heterostructures such as quantum wire and quantum dot. For nanostructures, surface condition would affect the quantum-effect substantially. Therefore, it is important to suppress the effect of dry etching process by defect-free, atomically smooth etching profile, and control of etching selectivity. Plasma dry etching such as reactive ion etching process induces the etched defect since it has high energy ultraviolet (UV) photon irradiation and charged particles. The etched defect would reduce the optical and electrical properties of semiconductor materials. Alternatively, neutral beam has great potential for developing a defect-free dry etching process by its characteristics of completely suppressing UV photon irradiation and only generating the low energy neutral beam (below 100eV). In this work, we study on a GaAs/Al0.3Ga0.7As heterostructure etching process by neutral beam etching with chlorine and argon mixed etching gas. The effect of different mixed ratio of chlorine and argon has been investigated. The results shows when 100% chlorine neutral beam used, the etching grass formation was observed on etched surface. To increase the argon mixed ratio in etched gas, the grass was eliminated and the etched surface roughness was smoother. As the best we know until now, when the 22% chlorine and 78% argon of mixed etched gas used, both the root-mean-square (rms) etched surface roughnesses of GaAs and Al0.3Ga0.7As are about 0.6 nm (the rms surface roughness of as-received sample is about 0.4nm). Meanwhile, the etching rate of GaAs and Al0.3Ga0.7As are 16 nm/min and 17 nm/min, respectively. It means the etching selectivity of GaAs/Al0.3Ga0.7As is about 0.94. Additionally, to verify the defect-free property of neutral beam etching, the cross-section of etched GaAs etched profile was analyzed by transmission electron microscopy. The result shows that no crystalline defect can be observed at the top region of etched surface. In summary, we developed a promising dry etching process for nanometer-scale GaAs/Al0.3Ga0.7As heterostructure with defect-free, etching selectivity of GaAs/Al0.3Ga0.7As closes to 1, and atomically smooth etching surface roughness.