AVS 66th International Symposium & Exhibition
    Atomic Scale Processing Focus Topic Thursday Sessions
       Session AP-ThP

Paper AP-ThP1
Atomic Resolution Characterization of Atomic Layer Etching Normally-off AlGaN/GaN Hetrostructure Device by Using Aberration-corrected STEM

Thursday, October 24, 2019, 6:30 pm, Room Union Station B

Session: Atomic Scale Processing Poster Session
Presenter: Chien-Nan Hsiao, Taiwan Instrument Research Institute, National Applied Research Laboratories, Taiwan, Republic of China
Authors: C.N. Hsiao, Taiwan Instrument Research Institute, National Applied Research Laboratories, Taiwan, Republic of China
C.P. Lin, National Applied Research Laboratories, Taiwan, Republic of China
C.C. Chen, National Applied Research Laboratories, Taiwan, Republic of China
M.H. Chan, National Applied Research Laboratories, Taiwan, Republic of China
W.-C. Chen, National Applied Research Laboratories, Taiwan, Republic of China
F.Z. Chen, National Applied Research Laboratories, Taiwan, Republic of China
Correspondent: Click to Email
An in-situ plasma enhanced atomic layer etching system has been design and fabricated. N2O , BCl3 and Ar plasma were used as the precursor for III-group epitaxy layer at various temperature. The optical detector was used to in-situ monitor the plasma spectrum during the step by step etching process. The AlGaN/GaN hetrostructure of normally-off high power GaN device (150 V) and etching per cycle of ALE were investigated using an aberration-corrected scanning transmission electron microscope with energy distribution spectrometer. It is found that the layer by layer etching feature shows the process is a controlled self-limited reaction. In addition, the influence of various aberration coefficients such as defocus, astigmatism, coma, spherical aberration and star aberration on the shape of the probe and more importantly on the electron intensity distribution within the probe was calculated. The accuracy required for compensation of the various aberration coefficients to achieve sub-angstrom resolution (0.078 nm) with the electron optics system was evaluated by the calculation of phase shift. Furthermore, the saturation curve of atomic etching rate and precursor pulsed time has been established. The etching per cycle of AlGaN is around 0.33 nm.