Abstract— Silvaco TCAD simulations are employed to identify relevant current carrying mechanisms in amorphous selenium (a-Se) based detectors, using parameters obtained from experimental data, density functional theory calculations, and in-house bulk Monte Carlo simulations. The steady-state dark current behaviors in various a-Se detectors are analyzed by identifying all relevant current conduction mechanisms (e.g., space-charge limited current, bulk thermal generation, Schottky emission, Poole-Frenkel activated mobility and hopping conduction), as well as “acceptor” and “donor” defect density of states located in the forbidden band gap of a-Se. The theoretical models are validated by comparing them with experimental steady-state dark current densities in avalanche and non-avalanche a-Se detectors.

Abstract— A Singular Point Source MOS (S-MOS) cell concept suitable for power MOS based devices is presented. The S-MOS differs from a standard Planar or Trench MOS cell in the manner by which the total channel width per device area is devised. The S-MOS single cell channel width is defined as the peripheral length of a line running approximately along the N++ source and P channel junction which is positioned on a gated trench side-wall. The length of the line is established from a singular point implant source for forming the N++ source region which geometrically corresponds to the shape of the N++/P junction. The N++ and PChannel profiles achieved are similar to those for a planar cell, but for the S-MOS, they are situated on a trench side-wall. The total device channel width will therefore depend on the total number of gated trench side-walls per chip. The S-MOS provides a unique approach for MOS cell layout designs and is applicable to different MOS based power devices. In this paper, the S-MOS is implemented on a 1200V IGBT by means of 3D-TCAD simulations while providing results highlighting the potential advantages with respect to the device static and dynamic performance.
Keywords – MOS cell, Insulated gate bipolar transistors.