AVS 53rd International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS1-FrM

Paper PS1-FrM10
Reduction of UV Irradiation Damage in CCD Image Sensor using CF@sub 3@I Gas Plasma

Friday, November 17, 2006, 11:00 am, Room 2009

Session: Plasma-Surface Interactions III
Presenter: Y. Ichihashi, Tohoku University and Sanyo Electric Co., Ltd., Japan
Authors: Y. Ichihashi, Tohoku University and Sanyo Electric Co., Ltd., Japan
Y. Ishikawa, Tohoku University, Japan
R. Shimizu, Sanyo Electric Co., Ltd, Japan
H. Mizuhara, Sanyo Electric Co., Ltd, Japan
M. Okigawa, Sanyo Electric Co., Ltd, Japan
S. Samukawa, Tohoku University, Japan
Correspondent: Click to Email
The generation of the SiO@sub 2@/Si interface states is one of the most serious problems for the metal-insulator silicon (MIS) devices such as charge-coupled devices (CCDs) or memories. For CCDs, the generation of the interface state causes the increase in dark current. We previously reported that the interface state in MIS devices were increased by the UV irradiation during the plasma process. Especially, the UV wavelength of 200 nm to 350 nm, which induced by C@sub x@F@sub y@ high-molecular-weight radicals, generates the interface states. Namely, the elimination of UV wavelength of 200 nm to 350 nm could keep the low-density interface state even after the etching process. In this paper, we propose the CF@sub 3@I gas plasma for the reduction of interface state density during the dielectric film etching process. By using the CF@sub 3@I plasma, a large amount of CF@sub 3@@super +@ are effectively generated without C@sub x@F@sub y@ radicals. As a result, no UV photon of 200 nm to 350 nm were observed in the plasma. Additionally, CF@sub 3@I is known as a gas for low global warming potential (GWP). For example, the GWP for CF@sub 3@I is about 1/1600 of C@sub 4@F@sub 8@ GWP. To solve the reduction of UV irradiation damage and the global warming improvement at the same time, we actually investigated the effect of the CF@sub 3@I plasma for the reduction in MIS devices. We used inductively coupled plasma with CF@sub 3@I and C@sub 4@F@sub 8@ gases. The plasma irradiation damages were evaluated by using MIS-FET as charge pumping current (Icp), and we measured UV spectra of plasma. The Icp was drastically reduced by using the CF@sub 3@I plasma comparing with C@sub 4@F@sub 8@ plasmas. In CF@sub 3@I plasma, no UV photon of 200 nm to 350 nm induced were observed.