CMOS Image Sensors and Plasma Processes: How PMD Nitride Charging Acts on the Dark Current

Abstract

Plasma processes are known to be prone to inducing damage by charging effects. For CMOS image sensors, this can lead to dark current degradation both in value and uniformity. An in-depth analysis, motivated by the different degrading behavior of two different plasma processes, has been performed in order to determine the degradation mechanisms associated with one plasma process. It is based on in situ plasma-induced charge characterization techniques for various dielectric stack structures (dielectric nature and stack configuration). A degradation mechanism is proposed, highlighting the role of ultraviolet (UV) light from the plasma in creating an electron hole which induces positive charges in the nitride layer at the wafer center, and negative ones at the edge. The trapped charges de-passivate the SiO2/Si interface by inducing a depleted interface above the photodiode, thus emphasizing the generation of dark current. A good correlation between the spatial distribution of the total charges and the value of dark current has been observed.

Turning Image Sensors into Position and Time Sensitive Quantitative Colorimetric Data Sources with the Aid of Novel Image Processing/Analysis Software

“…As an initial step, PicMan has been developed as a standalone image processing/analysis software platform for a variety of applications including semiconductor, material science, MEMS, chemistry, biological, pharmaceutical, medical, cultural heritage, and emerging applications [ 9 , 10 , 11 , 14 ]. An understanding of physics of image sensors and development of additional functions of image sensors will broaden the field of applications [ 19 , 20 ]. Hyperspectral image sensing and remote sensing applications are also actively investigated [ 4 , 21 ].…”

Silicon surface passivation with a-Si:H by PECVD: growth temperature effects on defects and band offset

“…The surface passivation of crystalline silicon is important for electronic devices such as high-efficiency solar cells, [1][2][3][4][5] lownoise image sensors, 6,7) and high-performance FETs. [8][9][10][11] The surface passivation is usually obtained with a ≈10 nm thick passivation layer of wide-bandgap materials coated on the silicon surface.…”