InGaAs-Based MSM Photodetector: Researching Absorption Layer, Barrier Layer, and Digital Graded Superlattice Layer with 3D Simulation

The effects of absorption, barrier, and digital graded layer thickness on dark current and photocurrent in Metal Semiconductor Metal (MSM) photodetectors by using 3D Silvaco TCAD are reported. The photo-dark current ratio (Iphoto/Idark) is calculated using the photocurrent and dark current values obtained by simulation. In study A (absorption layer thickness variation) the photocurrent, dark current and photo-dark current ratio are increased with increased absorption layer thickness, and the dark current is 1.138x10-7 A levels. In Study B (barrier layer thickness variation), when the barrier layer is added to the absorption layer, the dark current is decreased to 1.56x10-11 A levels. It is reported that the photo-dark current ratio with increasing barrier layer thickness increases. In study C (digital graded superlattice layer thickness variation), the dark current increases, and photocurrent decreases with the increase of the digital graded superlattice layer thickness. However, the photodark current ratio with increasing digital graded superlattice layer thickness decreases. Furthermore, a similar trend of development is observed on photo-dark current with adding of the barrier layer and digital graded superlattice layer on the absorption layer. These findings demonstrate the importance of optimizing layer thickness in MSM photodetectors for improved device performance.