InGaAs low table face linear array or face array infrared detector chip

Abstract

The invention discloses an InGaAs low table line array or area array infrared detector chip, comprising: forming line array or area array p-InP micro-mesas on a p-InP / InGaAs / n-InP epitaxial wafer by etching. There is an Au / Zn / Pt / Au / P electrode area in ohmic contact with the p-InP micro-mesas, and there is an etching to the n-InP layer on the side of the line or array micro-mesas and placed on the n-InP layer The common N electrode area. Except for the P and N electrode regions, the entire epitaxial wafer, including the sides, is covered with a silicon nitride passivation layer. An electrode interconnection area interconnected with the readout circuit is placed on the P electrode area, and the electrode interconnection area covers part of the micro-mesas and extends from the micro-mesas to the plane. The invention has the advantages that the reserved InGaAs layer can reduce the mesa and the side of the InGaAs layer is effectively protected. The silicon nitride passivation layer can effectively play the role of anti-reflection and reduce the surface state of the InP and InGaAs layer, and can increase the quantum efficiency of the detector and reduce the dark current. The P electrode adopts AuZnPtAu, which can form a good ohmic contact with p-InP, and Pt can effectively prevent the outdiffusion of Zn and improve the reliability of the device.

Description

technical field [0001] The invention relates to an infrared detector, in particular to a p-InP / InGaAs / n-InP (PIN) low-level line array or area array infrared detector chip. Background technique [0002] At present, PIN InGaAs detectors are mainly divided into two types: planar type and mesa type. Most planar PIN InGaAs detectors use Zn diffusion method to achieve p-type doping in the n-InP / InGaAs / n-InP cap layer InP. This method can obtain an InGaAs detector with a higher detection rate, but it has some unavoidable disadvantages: the diffusion process is complicated, the photosensitive surface is enlarged, and Zn diffusion will cause a large number of defects in the InP layer, which limit the indium GaAs detector performance enhancement. The mesa-type InGaAs detector is to etch the p-InP / InGaAs in the epitaxial material into a mesa, the cap layer p-InP is relatively thin, generally 0.1-0.5 μm, and the InGaAs absorption layer is thick, generally 1.5-3 μm . The advantage o...

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Problems solved by technology

This method can obtain an InGaAs detector with a higher detection rate, but it has some unavoidable disadvantages: the diffusion process is complicated, the photosensitive surface is enlarged, and Zn diffusion will cause a large number of defects in the InP layer, which limits the indium Performance Improvement of GaAs Detectors

The advantage of this structure is that the process is relatively simple, and the disadvantage is that the side exposure of the thicker absorbing layer introduces a large number of interface states, which limits the improvement of the device detection rate to a large extent, and poor side passivation will make the device reliable. decreased sex

In addition, it is also a difficult problem to reliably realize the extraction of ohmic contact electrodes on the p-InP cap layer

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