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Improved thermal treatment process for neutron-doped crystal

A process method and technology of doping silicon, applied in the directions of post-processing, crystal growth, post-processing details, etc., can solve the problems of metal element contamination, reduction of minority carrier lifetime parameters, improper heating and cooling rate, etc. The effect of minority carrier life and simple treatment process

Active Publication Date: 2012-11-28
GRINM SEMICONDUCTOR MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] 1. Neutron-doped single crystals are contaminated with some metal elements, and the cleaning is not thorough, and the residual metal elements directly lead to the decrease of the minority carrier lifetime parameters;
[0011] 2. Improper heating and cooling rates will cause the crystal to crack or even crack due to uneven heating;

Method used

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  • Improved thermal treatment process for neutron-doped crystal
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] In step 1 of the present invention, the crystal to be treated is first cleaned with pure water, and then acid-etched with a mixed acid solution of a specific ratio (such as nitric acid and hydrofluoric acid mixed at 3:1 or 5:1), and after fully corroded Then rinse with plenty of pure water.

[0039] The setting of the heat treatment temperature curve in step 2 of the present invention is mainly trapezoidal, wherein there are two temperature control points that are more critical, namely T1 (first temperature) (T1=T3) and T2 (second temperature), choose T1 in this experiment is 600°C and T2 is 800°C. The temperature control curve runs for about 10 hours. As shown in the figure below, the level of T1 and T2 will directly affect the recovery of crystal lattice damage, that is, affect the final minority carrier lifetime of the crystal.

[0040] In step 3, the selection of the spacer needs to be very strict. The spacer should not volatilize any metal elements at high temper...

Embodiment 2

[0048] Identical with other conditions in embodiment 1, choosing T1 in embodiment 2 is 650 ℃, and T2 is 850 ℃, and the heat treatment data obtained are as follows:

[0049] Crystal placement

Embodiment 3

[0051] Identical with other conditions in embodiment 1, choosing T1 in embodiment 2 is 700 ℃, and T2 is 900 ℃, and the heat treatment data obtained are as follows:

[0052] Crystal placement

[0053] From the data in Examples 2 and 3, it can be seen that within the specified temperature range and other conditions are the same, the minority carrier lifetime values ​​are equivalent. The criterion for determining the performance of the final product of the present invention is: the minority carrier lifetime parameter of the single crystals heat-treated simultaneously in this batch.

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Abstract

The invention relates to a thermal treatment process for a neutron-doped crystal, which comprises the following steps of: (1) cleaning the neutron-doped crystal: cleaning with pure water, undergoing chemical reaction with a mixed acid and then cleaning, wherein the volume ratio range of nitric acid to hydrofluoric acid in the mixed acid is from 8:1 to 3:1; (2) before thermal treatment, placing spacers on both ends of a sample, and carrying out thermal treatment; (3) carrying out thermal treatment on the crystal according to a certain heating process; and (4) after the thermal treatment process is completed, sand-blasting or grinding the surface of the crystal, and inspecting the crystal to verify the effect of the process. The invention has the advantages of simple and convenient treatment process and good effect, and the minority carrier lifetime of the thermally treated crystal can be prolonged.

Description

technical field [0001] The invention relates to a heat treatment method for eliminating neutron radiation damage and activating transmuted phosphorus atoms. Specifically, it is to rearrange the lattice distortion elements in the doped crystal at high temperature to eliminate the damage of the doped crystal and achieve the expected electrical parameters. Background technique [0002] The isotope 30Si of silicon in nature accounts for about 3%, and is evenly distributed in silicon (28Si). In the reactor, neutrons react with 30Si: [0003] 30Si(n, γ)——31Si, [0004] 30Si reacts with neutrons and emits gamma rays to form unstable 31Si. 31Si has a half-life of 2.62 hours, decays into stable 31P, and emits β rays (electrons). 31Si——31P+e- [0005] The dosage of the intermediate irradiation is determined according to the P content (resistivity) of the primary single crystal and the target resistivity. (Atomic number 14 for Si and 15 for P in the periodic table) [0006] The ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B33/02
Inventor 王小红高源徐学红
Owner GRINM SEMICONDUCTOR MATERIALS CO LTD