Broadband photodiode for detection from visible light to infrared light

Abstract

The invention relates to a photodiode, which can expand an absorption band of a light and finish detection from a visible light band to an infrared light band (400nm to 1350nm). The photodiode has relatively high responsiveness on two important bands of 0.8-0.9 microns and 1.1-1.35 microns. The photodiode structurally comprises a heavily doped N-type Si substrate with an opening, wherein a lightly doped N-type Si epitaxial layer, heavily doped P-type Si and a table structure are sequentially laminated on the N-type Si substrate; the table structure comprises an intrinsic Ge buffer layer and heavily doped P-type Ge thereon; and a silicon dioxide dielectric layer and a passivation layer are sequentially laminated on the table. A metal contact cathode VR is arranged on the back surface of the N-type Si substrate; a first metal contact anode VAF is arranged on the heavily doped P-type Si; a second metal contact anode VAS is arranged on the heavily doped P-type Ge; and an anti-reflection layer is arranged on the back surface of the lightly doped N-type Si epitaxial layer.

Description

Technical field [0001] The invention relates to the field of semiconductor devices, in particular to a photodiode. Background technique [0002] In optical fiber communication systems, photodetectors are one of the indispensable key components. The short-distance, high-density optical fiber communication system and data transmission system in the 0.8μm~0.9μm band often use Si single crystal substrate or GaAs-based PIN photodetector, avalanche photodetector and silicon preamplifier hybrid integrated optical receiver . The 1.06μm~1.55μm optical fiber communication network usually uses Ge single crystal substrate or InP-based PIN photodetector, avalanche photodetector and silicon preamplifier hybrid integrated optical receiver. [0003] As one of the important branches, silicon photodiodes are widely used in visible light detection and imaging due to their good spectral response, low noise, long life and high compatibility with CMOS processes. Among them, PIN silicon photoelectric ...

AI Technical Summary

Problems solved by technology

However, due to the inherent characteristics of the energy band structure, Si single crystal materials have problems such as low absorption coefficient, long absorption length, and no response to the band above 1.1 μm for near-infrared light.

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