Extended One-Dimensional Analysis to Effectively Derive Quantum Efficiency of Various CMOS Photodiodes

• Published in: IEEE transactions on electron devices Vol. 54; no. 10; pp. 2659 - 2668
• Main Authors: Chen, O.T.-C., Wei-Jean Liu, Li-Kuo Dai, Ping-Kuo Weng, Far-Wen Jih
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 1-D analysis; Applied sciences; Boundary conditions; Charge carrier density; CMOS; CMOS integrated circuits; CMOS photodiode; Computer simulation; Continuity equation; Design. Technologies. Operation analysis. Testing; Dimensional analysis; Dopants; Efficiency; Electronics; Equations; Exact sciences and technology; Feasibility; Integrated circuits; Mathematical model; Minority carriers; Optoelectronic devices; Photodiodes; Quantum efficiency; Semiconductor device modeling; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Studies; surface recombination velocity; Interfacial layer; Performance evaluation; 1-D analysis; Minority carrier; Charge carrier density; Photodiode; CMOS photodiode; Boundary condition; Quantum yield; Steady state; Surface recombination; quantum efficiency; Continuity equation; Complementary MOS technology; Dimensional analysis; Optoelectronic device; Current density; surface recombination velocity
• DOI: 10.1109/TED.2007.904989
• ISSN: 0018-9383

This paper proposes an extended 1-D analysis to derive quantum efficiency of various commonly used CMOS photodiodes. The theoretical model of the CMOS photodiode with the n-/p-epitaxial/p + substrate (n-/p-epi/p + sub) structure is established from steady-state continuity equations, where most existing boundary conditions are applied. In particular, the minority carrier and current densities are continuous across the interface between two layers with the same dopant type. Models of the other commonly used CMOS photodiodes are also examined. Three CMOS photodiodes with n-/p-substrate (n-/p-sub), p + /n-/p-substrate (p + /n-/p-sub), and n-/p-epi/p + sub structures are fabricated and characterized to validate the proposed model. Additionally, the surface recombination velocity is adequately determined by fitting the simulated quantum efficiency to the measured value. The simulated quantum efficiency of the proposed model for these three photodiodes is quite consistent with the measured values, revealing the feasibility and effectiveness of the proposed model in characterizing various CMOS photodiodes.