• Acta Photonica Sinica
  • Vol. 51, Issue 2, 0251218 (2022)
SHE Shixian, ZHANG Ye, HUANG Zhiwei, ZHOU Jinrong, and KE Shaoying*
Author Affiliations
  • College of Physics and Information Engineering,Minnan Normal University,Zhangzhou,Fujian 363000,China
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    DOI: 10.3788/gzxb20225102.0251218 Cite this Article
    Shixian SHE, Ye ZHANG, Zhiwei HUANG, Jinrong ZHOU, Shaoying KE. Effect of the Thickness of the a-Si Bonding Layer at InGaAs/Si Bonded Interface on the Performance of InGaAs/Si Avalanche Photodiode[J]. Acta Photonica Sinica, 2022, 51(2): 0251218 Copy Citation Text show less

    Abstract

    Avalanche Photodiode (APD) is a popular device for the detection of light with low energy. It has been commonly used in LIDAR, quantum communication, deep space application, and remote sensing. In comparison to visible light detection, extending the spectral range of the APD into the short-wave infrared region (especially 1 310 nm and 1 550 nm) has a number of competitive advantages, such as high atmospheric transmission through smoke, smog, and fog, high compatibility with low-loss fiber communication, enhanced eye-safety threshold for free-space exploration, and low solar radiation background level for single-photon detection. The combination of InGaAs material and Si material is an ideal solution for the fabrication of high-performance APDs for the detection of weak light at communication band due to the fact that the absorption coefficient of InGaAs material is high at near-infrared range and Si material exhibits excellent avalanche characteristic thanks to the low electron/hole ionization coefficient ratio (0.02). However, due to the 7.7% lattice mismatch between InGaAs and Si, high-density threading dislocations form in Si-based epitaxial InGaAs film, leading to the high dark current and high noise in InGaAs/Si APD. While, high-quality Si-based InGaAs film can be achieved by InGaAs/Si hetero wafer bonding and layer exfoliation. The InP-based epitaxial InGaAs thin film is bonded to the Si-based epitaxial Si film by direct bonding method. This is a potential method for the fabrication of high-performance InGaAs/Si APD. However, the reported direct wafer bonding technique still cannot isolate the lattices of InGaAs and Si fundamentally due to the fact that the lattices of InGaAs and Si is directly contacted to each other during bonding, leading to the formation of misfit dislocations at the bonded interface. Thus, the lattices of InGaAs and Si materials should be segregated for the elimination of nucleation of dislocations. Using amorphous semiconductor intermediate layer, the lattice between InGaAs and Si can be isolated thoroughly. In addition, the quality of InGaAs absorption layer and Si multiplication layer, and good carrier transport at bonded interface can be ensured. However, the effect of a-Si material with high defect density and lager bandgap on the performance of InGaAs/Si APD has never been reported. In this paper, we first simulate the effect of the thickness of a-Si bonding layer on the performance of InGaAs/Si APD. Ultra-low dark current of the device is achieved at room temperature. Besides, when the bias is larger than breakdown voltage, a current gap appears between optical current and dark current. Extremely low dark current is achieved. This may give guidance for the fabrication of low-noise InGaAs/Si APD.