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

Abstract

The invention discloses an InGaAs low mesa line series or area array infrared detector chip, which includes a line series or area array p-InP micro-mesa formed by etching on p-InP / InGaAs / n-InP epitaxial wafer. The p-InP micro-mesa is provided with an Au / Zn / Pt / Au / P electrode area in ohmic contact. A public N electrode area is etched to the n-InP layer on the side of the line series or area array micro-mesa and is positioned on the n-InP layer. Except for the P and N electrode areas, the whole epitaxial wafer and the lateral sides are covered by a silicon nitride passivation layer. The P electrode area is provided with an electrode interconnection area with a reading circuit. The electrode interconnection area covers a part of the micro-mesa and extends from the micro-mesa to a plane. The invention has the advantages of mesa decrease by retained InGaAs layer and effective protection on the InGaAs layer lateral sides. The silicon nitride passivation layer has effective function of reflection resistance and InP and InGaAs layer surface state reduction and can increase the detector quantum efficiency and decrease dark current. The P electrode adopts AuZnPtAu, forms good ohmic contact with p-InP and P can effectively prevent Zn from out diffusion and improve the device reliability.

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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