Optimization Strategy of 4H-SiC Separated Absorption Charge and Multiplication Avalanche Photodiode Structure for High Ultraviolet Detection Efficiency

Abstract

In this work, parametric investigations on structural optimization are systematically made for 4H-SiC-based separated absorption charge and multiplication (SACM) avalanche ultraviolet photodiode (UV APD). According to our results, the breakdown voltage can be strongly affected by the thickness for the multiplication layer and the doping concentration for the charge control layer. The thickness for the n-type ohmic contact layer, the absorption layer, and the charge control layer can remarkably affect the light penetration depth, which correspondingly influences the number of photo-generated electron-hole pairs, and therefore the aforementioned layer thickness has a strong impact on the responsivity for SACM APD. For enhancing the responsivity of the APD, we require a reduced energy band barrier height at the interface of the optical absorption layer and the charge control layer, so that the promoted carrier transport into the multiplication layer can be favored. In addition, we investigate positive beveled mesas with smaller angles so as to reduce the electric field at the mesa edge. Thus, the dark current is correspondingly suppressed.

Characterization and Fabrication of the CFM-JTE for 4H-SiC Power Device with High-Efficiency Protection and Increased JTE Dose Tolerance Window

“…The existence of surface states should be considered in the actual fabrication of the 4H-SiC PiN rectifier. These surface states are derived from holes trapped in deep interface states, fixed oxide charges of P-SiC (including P ++ layer and P-JTE region)/SiO 2 interface and the implementation process [15][16][17][18]. For the CFM-JTE termination, the electric field modulation at the interface S 1 and S 2 by interface positive charges (Q it ), effective charges (Q j ) and applied potential in the direction of the vertical is analyzed in Fig.…”

GaAs/Al0.8Ga0.2As separate absorption and multiplication region x-ray spectroscopic avalanche photodiodes

“…APDs are widely used in photonic detection systems, most notably within telecommunications [30][31][32][33], to improve response relative to that of conventional p + -i-n + photodiodes [30]. The increased response from such APDs is due to the impact ionisation process, where charge carriers gain enough kinetic energy to generate electron-hole pairs during collisions with atoms in the lattice [34,35].…”

High‐uniformity 1 × 64 linear arrays of silicon carbide avalanche photodiode

“…Introduction: Silicon carbide (SiC) avalanche photodiodes (APDs) have been greatly investigated in recent years as the candidates for ultraviolet (UV) detectors to replace the conventional expensive, bulky and fragile photomultiplier tubes, which is of very importance in many applications such as flame detection, astronomical research, biochemical analysis and UV communication [1][2][3][4][5][6][7][8][9][10]. However, most of the previously reported works focus on the discrete device, while the research on 4H-SiC APD arrays is barely reported [11][12][13][14].…”

“…Device design and fabrication: The 4H-SiC epi-layer structure in this work was carefully designed according to the work in [10]. Separate absorption charge multiplication epi-layer structure is used, as shown in Fig.…”