Search

In this paper, a new model of the frequency dependence of the double-barrier THz rectifier is presented. The new structure is of interest because it can be realized by CMOS image sensor technology. Its application in a complex field such as that of THz receivers requires the availability of an analytical model, which is reliable and able to highlight the dependence on the parameters of the physical structure. The model is based on the hydrodynamic semiconductor equations, solved in the small signal approximation. The model depicts the mechanisms of the THz modulation of the charge in the depleted regions of the double-barrier device and explains the self-mixing process, the frequency dependence, and the detection capability of the structure. The model thus substantially improves the analytical models of the THz rectification available in literature, mainly based on lamped equivalent circuits. [ABSTRACT FROM AUTHOR]

This paper proposes a 256 × 256 time-of-flight (TOF) image sensor based on the center-tap (CT) demodulation pixel structure. The image sensor can capture both the two-dimensional (2D) high speed image and the three-dimensional (3D) depth image. The CT pixel consists of two split pinned photodiode (PPD) regions and two pairs of transfer transistors. The transfer transistors adopt a non-uniform doped channel (NUDC) structure, which can increase the electron transfer speed along the transfer channel and eliminate the image lag for high speed imaging. The pixel size is 10 µm × 10 µm, and we design the implementation process of the pixel to increase the electron transfer speed. The sensor is fabricated in a 0.18 µm 1P5M CMOS image sensor process. Test results show that it can capture the 430-fps intensity image and the 90-fps depth image in two different imaging modes. The rectified non-linearity within the 1.0-7.5 m depth measurement range achieves less than 3 cm, and the measurement accuracy achieves 4.0 cm at 2.5 m, corresponding to the relative error of 1.6%. [ABSTRACT FROM AUTHOR]

The article details the fabrication of a 32x32 silicon on insulator complementary metal oxide semiconductor active pixel image sensor with a pinned photodiode on a handle wafer. It describes the structure of one pixel which consists of a reset and a source follower transistor on a seed wafer. The article shows that photodiode could be optimized for better quantum efficiency and low dark currents.