Method for improving uniformity of doping concentration of silicon epitaxial layer for photosensor

A photoelectric sensor and doping concentration technology, which is applied in the direction of circuits, electrical components, semiconductor devices, etc., can solve the problems of poor consistency and achieve the effect of improving the consistency of distribution

Active Publication Date: 2018-08-17
CHINA ELECTRONICS TECH GRP NO 46 RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the problem that the doping concentration of the P-type silicon epitaxial layer used in the existing photoelectric sensor is affected by self-doping in the chip and between the chips, and the consistency is poor. By implementing the main process before the growth of the doped epitaxial layer The rapid change of the gas flow rate and the two intrinsic layer growth processes sweep most of the impurities volatilized at high temperature out of the cavity, reducing the influence of substrate impurities on the self-doping during the growth of the epitaxial layer, and obtaining a A preparation method for improving the uniformity of doping concentration of silicon epitaxial layer for photoelectric sensors

Method used

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  • Method for improving uniformity of doping concentration of silicon epitaxial layer for photosensor
  • Method for improving uniformity of doping concentration of silicon epitaxial layer for photosensor

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Embodiment 1

[0028] In the first step, hydrogen gas is introduced into the reaction chamber, and the flow rate of hydrogen gas is set to 20 L / min. Then, hydrogen chloride gas is introduced, and the flow rate of hydrogen chloride gas is set to 30 L / min. etched, the reaction temperature was set at 1080°C, and the reaction time was set at 5 min; in the second step, the flow rate of hydrogen gas was set at 150 L / min, gaseous trichlorosilane was introduced, and the flow rate was set at 6 L / min, and the deposition The time was set at 2 min, and the surface of the epitaxial reaction base was covered with a layer of undoped polysilicon.

[0029] The third step is to install the silicon substrate on the polysilicon layer on the epitaxial reaction base, and use nitrogen and hydrogen to purge the epitaxial reaction chamber in sequence. The flow rate of nitrogen gas is set to 100 L / min, and the flow rate of hydrogen gas is set to 150 L / min. L / min, the chamber purge time was set to 10 min.

[0030] Th...

Embodiment 2

[0037]In the first step, hydrogen gas is introduced into the reaction chamber, and the flow rate of hydrogen gas is set to 20 L / min. Then, hydrogen chloride gas is introduced, and the flow rate of hydrogen chloride gas is set to 30 L / min. Corrosion, the reaction temperature was set at 1080 °C, and the reaction time was set at 5 min;

[0038] In the second step, set the flow rate of hydrogen to 150 L / min, pass through gaseous trichlorosilane, set the flow rate to 6 L / min, set the deposition time to 2 min, and cover the surface of the base with a layer of undoped Polysilicon;

[0039] The third step is to install the silicon substrate on the polysilicon on the epitaxial reaction base, and then use nitrogen and hydrogen to purge the epitaxial reaction chamber in sequence. The flow rate of nitrogen gas is set to 100 L / min, and the flow rate of hydrogen gas is set to 150 L / min, the chamber purge time is set to 10 min.

[0040] The fourth step is to heat the epitaxial reaction ba...

Embodiment 3

[0048] In the first step, hydrogen gas is introduced into the reaction chamber, and the flow rate of hydrogen gas is set to 20 L / min. Then, hydrogen chloride gas is introduced, and the flow rate of hydrogen chloride gas is set to 30 L / min. etched, the reaction temperature was set at 1080 °C, and the reaction time was set at 5 min.

[0049] In the second step, set the flow rate of hydrogen to 150 L / min, feed gaseous trichlorosilane, set the flow rate to 6 L / min, set the deposition time to 2 min, and cover the surface of the epitaxial reaction base with a layer of non-doped Miscellaneous polysilicon.

[0050] The third step is to install the silicon substrate on the polysilicon on the epitaxial reaction base, and then use nitrogen and hydrogen to purge the epitaxial reaction chamber in sequence. The flow rate of nitrogen gas is set to 100 L / min, and the flow rate of hydrogen gas is set to 150 L / min, the chamber purge time is set to 10 min.

[0051] The fourth step is to heat ...

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Abstract

The invention relates to a method for improving the uniformity of doping concentration of a silicon epitaxial layer for a photosensor. The method includes the steps of introducing hydrogen and hydrogen chloride gas into a reaction chamber; coating the surface of an epitaxial reaction substrate with an undoped polysilicon layer; loading a silicon base sheet onto the polysilicon, and purging the epitaxial reaction chamber sequentially with nitrogen and hydrogen; heating the epitaxial reaction substrate; introducing hydrogen chloride gas to polish the surface of the silicon base sheet; purging the reaction chamber by quick periodic alternating variation of flow; growing a first intrinsic epitaxial layer; introducing hydrogen into the reaction chamber for purging; growing a second intrinsic epitaxial layer; purging the reaction chamber by quick periodic alternating variation of flow; growing a doped epitaxial layer; and after the growth of the epitaxial layer is completed, stopping heating, and finally taking out the chip. The beneficial effect is that the on-chip non-uniformity is reduced from 5.09% to the level of 1.48%, the control capability is improved, and the process capabilitycan meet the requirements of users.

Description

technical field [0001] The invention relates to the technical field of preparation of semiconductor epitaxial materials, in particular to a method for improving the doping concentration uniformity of a silicon epitaxial layer for a photoelectric sensor. Background technique [0002] At present, photoelectric sensors represented by CCD devices are developing towards high-speed development of high sensitivity, high resolution, and wide dynamic range. It is urgently required that the doping concentration of the P-type silicon epitaxial layer as a key supporting material has a high consistency to meet The working voltage, sensitivity and other index requirements of the device. However, since the growth of the silicon epitaxial layer is based on the heavily doped boron impurity substrate, the boron atom has the characteristics of light weight, long free path, and extremely volatile. At an epitaxial reaction temperature higher than 1000°C, the volatilization effect of substrate im...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/02H01L31/0288H01L31/101
CPCH01L21/02532H01L21/02595H01L21/02634H01L31/0288H01L31/101
Inventor 李明达周幸李杨
Owner CHINA ELECTRONICS TECH GRP NO 46 RES INST
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