作者
Y. Fujisaki,H. Tsugawa,K. Sakai,Hiroaki Kumagai,R. Nakamura,Tomoharu Ogita,S. Endo,Toshiki Iwase,Hiroshi Takase,Keiichi Yokochi,S. Yoshida,Shoichi Shimada,Yusuke Otake,T. Wakano,Hirokuni Hiyama,Kenta Hagiwara,M. Arakawal,S. Matsumotol,H. Maeda,K. Sugihara,Kazumasa Takabayashi,Masayoshi Ono,Koji Ishibashi,K. Yamamoto
摘要
We present a back-illuminated 3D-stacked 6 $\mu \mathrm{m}$ single-photon avalanche diode (SPAD) sensor with very high photon detection efficiency (PDE) performance. To enhance PDE, a dual diffraction structure was combined with $2\times 2$ on-chip lens (OCL) for the first time. A dual diffraction structure comprises a pyramid surface for diffraction (PSD) and periodic uneven structures by shallow trench for diffraction formed on the Si surface of light-facing and opposite sides, respectively. Additionally, PSD pitch and SiO 2 film thickness buried in full trench isolation were optimized. Consequently, a PDE of 36.5% was achieved at $\lambda=940$ nm, the world's highest value. Owing to shield ring contact, crosstalk was reduced by about half compared to a conventionally plugged one.