Extended wavelength indium gallium arsenide detector with composite passivation film structure and preparation method

Abstract

The invention discloses a wavelength extending indium gallium arsenic detector of a composite passive film structure and a manufacturing method. The manufacturing method comprises the specific steps that an epitaxial wafer is etched to form a p-type micro mesa; a P-electrode region is manufactured on the local area of the micro mesa, and an electrode interconnecting region covering part of the micro mesa is arranged on the P-electrode region, and extends from the upper portion of the micro mesa to the position below the micro mesa; an N-groove etched to an n-type buffer layer is formed in one side of the micro mesa, and an N-electrode region is manufactured. Except for the P-electrode region and the N-electrode region, the whole epitaxial wafer is covered with a composite passivation layer. The manufacturing method has the advantages that the Al2O3 / SiNx composite passive film structure can effectively cover the micro mesa, the side face passivation effect is improved, the interface state density is reduced, and the sensitivity of a device is improved; after high-temperature annealing, a Al2O3 / SiNx composite passive film is manufactured, external diffusion of In elements and degeneration of the insulation performance of the film are avoided, and the reliability of the device is improved.

Description

Technical field [0001] The invention relates to an indium gallium arsenide detector, in particular to an extended wavelength indium gallium arsenic detector with a composite passivation film structure and a preparation method. Background technique [0002] According to the response band In x Ga 1-x As detectors can be divided into two types: lattice matching and extended wavelength. Lattice matching In x Ga 1-x The In composition x of the As detector is 0.53. At this time, the InGaAs epitaxial material has the same lattice constant as the InP substrate, and the response cut-off wavelength of the device is 1.7μm; increase the In composition x and extend the wavelength In x Ga 1-x As detector can respond to 2.5μm (In composition x is 0.83). Wavelength extension can greatly expand the application fields of the detector, but the increase of In composition will cause In x Ga 1-x The lattice mismatch of As and InP substrate. Extended wavelength In x Ga 1-x This special structure of As...

AI Technical Summary

Problems solved by technology

SiN grown by PECVD x Passivation film at extended wavelength In x Ga 1-x Better process compatibility and device performance can be achieved on As detectors, but the film grown by PECVD has the following disadvantages: it contains more hydrogen elements and has poor compactness; the plasma power is high, resulting in increased interface state density and device damage; The growth temperature is high, and there is a certain thermal stress between the film and the substrate

These factors limit the improvement of device sensitivity, and usually in the device process, SiNx thin films will undergo high-temperature process of alloying, which will lead to the out-diffusion of In elements in the semiconductor at the interface and the degradation of the insulating properties of the film, thus affecting the reliability of the device.

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