Indium phosphide diffusion method

Abstract

The invention discloses an indium phosphide diffusion method, and relates to the technical field of a manufacturing method of a semiconductor device. The indium phosphide diffusion method comprises the steps of placing an indium phosphite wafer to be diffused into MOCVD equipment, adjusting the total gas flow in a reaction chamber of the MOCVD to a desired value, converting the nitrogen atmosphere into a hydrogen atmosphere, raising the temperature, performing surface protection, raising the temperature continuously and maintaining the constant temperature for a certain period of time; inputting a dimethyl zinc flow, adjusting the dimethyl zinc flow to a desired value, controlling the temperature of the MOSCVD equipment for linear decline, and performing zinc diffusion; cutting off the protection gas when the temperature drops below 430 DEG C-470 DEG C, enabling the temperature to drop to the room temperature in the hydrogen atmosphere, and taking out the wafer after the hydrogen atmosphere converts into the nitrogen atmosphere. According to the method, the diffusion concentration at different diffusion depths can be accurately controlled, a high hole concentration of 2e<18> at the surface of the wafer and a low hole concentration of 5e<17> inside the wafer are achieved, the diffusion uniformity is stable, and the method is applicable to mass production.

Description

technical field [0001] The invention relates to the technical field of manufacturing methods of semiconductor devices, in particular to an indium phosphide diffusion method. Background technique [0002] The indium phosphide-based avalanche detector is a kind of semiconductor detector, which is used in the optical signal receiving end in the field of optical communication, and its performance affects the efficiency and quality of optical communication. [0003] Compared with germanium-based detectors and indium phosphide-based PIN detectors that have been widely used at present, since indium-phosphide-based avalanche detectors use the principle of avalanche breakdown to convert light signals, they have higher responsivity and high photoelectric conversion Efficiency, and because of the excellent high-frequency characteristics of InP-based materials, the operating frequency can be made higher. Therefore, the demand for indium phosphide-based avalanche detectors in the curren...

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Problems solved by technology

This zinc diffusion process is difficult to control. It is controllable but not precisely adjustable. It cannot accurately control the hole concentration at different depths according to the detector design. In addition, the tube furnace diffusion process destroys the structure of the epitaxial material, and the uniformity of the wafer is poor. question

[0005] For the current zinc diffusion process using MOCVD equipment, a high dimethyl zinc flow rate is required to achieve a high hole concentration, and it is difficult to control the diffusion depth when the diffusion speed is fast. To achieve a low hole concentration, a low dimethyl zinc flow rate is required, and the diffusion speed Very slow, after a long time of zinc diffusion process, the surface crystal quality degrades, which affects the long-term working stability of the device

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