| AVS 65th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Monday Sessions |
| Session PS+AS+EM+SS-MoM |
| Session: | Plasma-Surface Interactions |
| Presenter: | Shota Nunomura, National Institute of Advanced Industrial Science and Technology (AIST), Japan |
| Authors: | S. Nunomura, National Institute of Advanced Industrial Science and Technology (AIST), Japan I. Sakata, National Institute of Advanced Industrial Science and Technology (AIST), Japan K. Matsubara, National Institute of Advanced Industrial Science and Technology (AIST), Japan |
| Correspondent: | Click to Email |
In state-of-the art semiconductor devices, electronic defects strongly influence the device performance. The electronic defects are often generated during the device fabrication, where a variety of plasma processing technology is used for film deposition，gate etching, dopant implantation and so on. Most defects are recovered by post-annealing, however some defects remain in the devices. Because these defects usually deteriorate the device performance, reduction of these defects is required. However, the kinetics of generation and annihilation of the defects are not fully understood yet.
We studied the kinetics of electronic defects in hydrogenated amorphous silicon (a-Si:H) during H2 and Ar plasma treatments. The generation and annihilation of defects are monitored via in-situ photocurrent measurement during the treatment [1-2]. A decrease in the photocurrent indicates the generation of defects whereas an increase in the photocurrent indicates the annihilation of defects. This photocurrent-based monitoring is highly sensitive in the detection of small amount of defect density (~1016cm-3).
The photocurrents in a-Si:H films under various conditions of H2 and Ar plasma were measured. From the measurements, we find the following [3]. (i) Each plasma treatment immediately causes the generation of defects, indicated by a strong reduction in the photocurrent. (ii) The defects are generated dominantly by the radicals such as hydrogen atoms (H) and argon metastable atoms (Ar*). (iii) The residual defects are created by the bombardment of Ar+ ions rather than H3+ ions, radicals and photons. However, the residual defects are recovered mostly by an additional H2 plasma and post-annealing treatment. (iv) The radicals and photons also generates defects, however these defects are annihilated by the simple post-annealing. The details of the experimental setup, results and discussion are given in the presentation.
This work was supported by JSPS KAKENHI (Grant Number 18K03603 and 15K04717) and NEDO.
[1] S. Nunomura, I. Sakata, and M. Kondo,Appl. Phys. Express 6, 126201 (2013). [2] S. Nunomura and I. Sakata, AIP Advances 4, 097110 (2014). [3] S. Nunomura et al., submitted.