Graded zinc diffusing method based on MOCVD (Metal-Organic Chemical Vapor Deposition) system for producing chip of indium-gallium-arsenic photoelectric detector

Abstract

The invention relates to a graded zinc diffusing method based on an MOCVD system for producing the chip of an indium-gallium-arsenic photoelectric detector. The method comprises the following steps: a semiconductor wafer which does not form an InGaAs PIN structure of a PN junction is cleaned and blown to dry by high-purity nitrogen; an MOCVD reaction chamber is heated up, depressurized and cleaned; the semiconductor wafer is placed in the reaction chamber; the pressure of the reaction chamber is set; diffusion taking a zinc phosphide compound which is formed by zinc methide (DMZn) and phosphorane (PH3) at high temperature as a diffusion source is conducted with the presence of catalytic reaction and the shielding gas; after the completion of the diffusion, the gas is turned off, the reaction chamber is cooled down and filled with nitrogen and has a pressure rise; and the wafer which undergoes the diffusion is taken out of the reaction chamber. As the diffusion rules of zinc in InP material and InGaAs material have great difference, the graded diffusion method is adopted. With the method, both the InP layer and the InGaAs layer can have rather high current carrier concentration, good interface, rather good homogeneity, technique repeatability, high response and precise control and can be manufactured on a large scale.

Description

technical field [0001] The invention relates to a gradual zinc diffusion method for making an indium gallium arsenic photodetector chip based on an MOCVD system. Background technique [0002] InP-based InGaAs PIN photodetectors are widely used in the field of optical fiber communication. As the core component of light receiving in communication, CATV system, and optoelectronic technology, its application space is very huge. The InP / InGaAs PIN detector epitaxial material is mainly prepared by MOCVD, and the epitaxial structure does not contain high-concentration P-type doping. The P-type InP or InGaAs ohmic contact layer required for device production is completed by various forms of Zn diffusion. Zn The traditional methods of diffusion include the closed tube diffusion method and the open tube diffusion method. The sample is in a closed or open quartz boat, and ZnAs and ZnP saturated vapor are used as the diffusion source. The advantage of the two methods is that the diffusi...

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Problems solved by technology

The InP / InGaAs PIN detector epitaxial material is mainly prepared by MOCVD, and the epitaxial structure does not contain high-concentration P-type doping. The P-type InP or InGaAs ohmic contact layer required for device production is completed by various forms of Zn diffusion. Zn The traditional methods of diffusion include the closed tube diffusion method and the open tube diffusion method. The sample is in a closed or open quartz boat, and ZnAs and ZnP saturated vapor are used as the diffusion source. The advantage of the two methods is that the diffusion equipment is simple, but there are the following problems: Because ZnAs and ZnP are not stable enough, the doping of P-InP is relatively low, about 1.8E+17 / cm3; the interface formed by InP and InGaAs is not clear enough, and it is easy to accumulate too much at the junction of InP and InGaAs interface. Too many charge particles, too much charge accumulation will also cause the absorption of redundant impurity particles, resulting in excessive dark current; the process is complicated and the process controllability is poor; the P-InP carrier concentration is too low, it is difficult to achieve good The ohmic contact of , is greatly restricted for making high linear devices.

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