Silicide-based photodetectors with localized surface plasmon resonance for mid-IR detection
Journal
Proceedings of SPIE - The International Society for Optical Engineering
Journal Volume
11741
Date Issued
2021
Author(s)
Abstract
Nowadays, infrared (IR) photodetectors are mainly made from compound semiconductors due to the bandgap flexibility. However, compound semiconductors are mostly synthesized by expensive and energy-intensive epitaxy processes. Moreover, compound semiconductors are difficult to integrate with Si-based IC industry. Therefore, we used n-type Si (n-Si) wafers and thin NiSi to combine with localized surface plasmon resonance (LSPR) to form a Schottky IR detector. The incident IR light can induce thermionic effect to generate photocurrent, and the LSPR can enhance the light absorption and improve the photoresponse. The LSPR was created by NiSi covered inverted-pyramid array structures (IPAS) formed on n-Si substrates through photolithography and etching processes. After IPAS were prepared, 10-nm-thick Ni was thermally deposited on the IPAS and then the entire samples were annealed under 500 ℃ in 5 s to form NiSi/n-Si Schottky junctions. Finally, Ti and Au were thermally deposited successively on the NiSi and the back of n-Si wafers to be electrodes. A planar device was also prepared to be a control part. The photodetection ability of the device was examined by a 4.8-μm IR source with 1.8-mW optical power, which is in the absorption range of carbon monoxide. The IR source was turned on/off for each 15 s. Consequently, the planar NiSi/n-Si Schottky photodetector shows average 9.37-μA current change under 4.8-μm IR source illumination in 15 s. However, if 8-μm-period IPAS was used, the average current change improved to 30.9 μA. The response enhancement is 3.30 times of the planar device. ? 2021 SPIE
Subjects
NiSi
Photodetector
Photoresponse
Plasmon
Schottky
Si
Silicide
Surface plasmon resonance
Carbon monoxide
Etching
Gold deposits
Infrared radiation
Light absorption
Nickel compounds
Photocurrents
Photodetectors
Photons
Plasmons
Silicides
Silicon wafers
Thermionic power generation
Average currents
Compound semiconductors
Etching process
Localized surface plasmon resonance
Photo detection
Schottky junctions
Schottky photodetectors
Thermionic effects
SDGs
Type
conference paper