Theoretical analysis and design of submicron-LAPS

Light addressable potentiometric sensors (LAPS) are important cell sensors. After the invention, much effort has been made to improve the spatial resolution in order to realize a single cell level measurement. In this paper, the concept of submicron-LAPS is proposed and researched theoretically to improve the spatial resolution to less than 1 μm. Modern semiconductor devices theories are used to study the minority carrier diffusion patterns, which determine the spatial resolution of LAPS. Based on the band energy theory, a physical model and corresponding mathematical models are proposed to estimate the spatial resolution. A new definition of spatial resolution is made in this paper to match the reported experimental results. The finite element analysis (FEA) method is used to solve the partial differential equations. Based on the simulation results, one novel structure, which combined the MEMS and MOSFET technologies, were studied theoretically to realize the concept of submicron-LAPS.