Diffusion device and method for zinc in photodetector fabrication

Abstract

The invention discloses a zinc diffusion device and a diffusion method thereof in manufacturing of a photoelectric detector. The device comprises a heating furnace, a quartz tube, a gas control system, a vacuum system, a quartz boat and a vacuum pushing device, wherein both ends of the quartz tube are sealed, the quartz boat is used for accommodating a diffusion source and an epitaxial wafer to be diffused, the vacuum pushing device is used for pushing the quartz boat into the quartz tube, one end of the quartz tube is positioned in a hearth of the heating furnace and is used as a constant-temperature area, the other end of the quartz tube is positioned on the outside of the hearth of the heating furnace, is used as a cooling area and is maintained in a room temperature state, the gas control system is used for filling nitrogen into the quartz tube, and the vacuum system is used for vacuumizing the quartz tube by a vacuum pipeline. The method has the advantages that the risk of using an oxy-hydrogen flame to seal the quartz tube in the traditional tube-closing diffusion process is avoided, the pollution at the epitaxial wafer by sucking residual slag into the quartz tube at the negative pressure in the quartz tube when the quartz tube is opened is avoided, and the problems of nonuniform temperature, difficult control of diffusion depth and overlong cooling time in the traditional tube-opening diffusion process are solved. The method is favorable for batch diffusion.

Description

technical field [0001] The invention relates to a zinc diffusion device and a diffusion method in the field of semiconductor optoelectronic devices, in particular to a novel zinc diffusion device and diffusion method in the manufacturing process of indium gallium arsenic photodetectors. Background technique [0002] Traditional indium gallium arsenic epitaxial wafers grow indium gallium arsenic absorber layer and intrinsic indium phosphide top layer on n-type indium phosphide base material by organic vapor phase epitaxy deposition (MOCVD), so it is necessary to go through various processes during the manufacturing process. A doping technique, such as: diffusion, ion implantation, etc., to form a P-type diffusion region. Because the diffusion process of zinc is simple, the surface damage of the epitaxial wafer is small, and excellent performance can be obtained, so it is widely used. [0003] The traditional closed-tube diffusion process is to put the epitaxial wafer and the...

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Problems solved by technology

[0003] The traditional closed-tube diffusion process is to put the epitaxial wafer and the diffusion source into the quartz tube, vacuumize it, then seal the quartz tube with a hydrogen-oxygen flame, and then put it into the furnace for diffusion. This method is complicated to operate and dangerous to use. The diffusion source and The quartz tube cannot be reused, and the diffusion of large-sized epitaxial wafers cannot be realized, and the surface of the epitaxial wafers is easily polluted

Although the traditional open-tube diffusion process can make the diffusion source and quartz tube reusable, and the operation is simple, but because the open-tube diffusion pressure fluctuates with the atmospheric pressure, and the furnace is pushed back and forth, the temperature fluctuation range is large, and the diffusion depth cannot be achieved with high precision. control

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