Granted Patent B2

US 12,351,466 · App. 17/601,460 · Granted Jul 8, 2025

Inventors: Takuya Asano (Yamaguchi, JP); Kouichi Saiki (Yamaguchi, JP); Miki Emoto (Yamaguchi, JP); Tooru Onoda (Yamaguchi, JP)

Assignee: Tokuyama Corporation

C01B33/035C30B15/36C30B29/06C01P2006/80

Abstract

Claims (21)

1. A polycrystalline silicon material for producing an n-type silicon single crystal having a resistivity of 10,000 Ωcm or more, comprising:

a plurality of polycrystalline silicon chunks, wherein

when a total concentration of donor elements present inside a bulk body of the polycrystalline silicon material is Cd1 [ppta], a total concentration of acceptor elements present inside the bulk body of the polycrystalline silicon material is Ca1 [ppta], a total concentration of the donor elements present on a surface of the polycrystalline silicon material is Cd2 [ppta], a total concentration of the acceptor elements present on the surface of the polycrystalline silicon material is Ca2 [ppta], and a difference between a sum of Cd1 and Cd2 and a sum of Ca1 and Ca2 is an effective donor element concentration,

the effective donor element concentration satisfies a relation of 2 [ppta]≤(Cd1+Cd2)−(Ca1+Ca2)≤8 [ppta].

2. The polycrystalline silicon material according to claim 1 , wherein when a total weight of the polycrystalline silicon chunks contained in the polycrystalline silicon material is 100%, a weight of polycrystalline silicon chunks having a maximum length of 10 mm or more and 45 mm or less is 90% or more.

3. The polycrystalline silicon material according to claim 1 , wherein when a total weight of the polycrystalline silicon chunks contained in the polycrystalline silicon material is 100%, a weight of polycrystalline silicon chunks having a maximum length of 20 mm or more and 70 mm or less is 90% or more.

4. The polycrystalline silicon material according to claim 1 , wherein when a total weight of the polycrystalline silicon chunks contained in the polycrystalline silicon material is 100%, a weight of polycrystalline silicon chunks having a maximum length of 60 mm or more and 100 mm or less is 90% or more.

5. The polycrystalline silicon material according to claim 1 , wherein:

a total concentration of bulk donor elements phosphorous and arsenic, Cd1, is in a range of 10 to 60 [ppta];

a total concentration of bulk acceptor elements boron and aluminum, Ca1, is in a range of 1 to 4 [ppta];

a total concentration of surface donor elements phosphorous and arsenic, Cd2, is in a range of 1 to 30 [ppta]; and

a total concentration of surface acceptor elements boron and aluminum, Ca2, is in a range of 10 to 70 [ppta].

6. A method for producing an n-type silicon single crystal, comprising:

producing a polycrystalline silicon rod while controlling a bulk dopant concentration of the polycrystalline silicon rod;

cutting and crushing the polycrystalline silicon rod to form polycrystalline silicon nuggets;

washing the polycrystalline silicon nuggets;

controlling a surface dopant concentration of the polycrystalline silicon nuggets to obtain the polycrystalline silicon material according to claim 1 ; and

producing an n-type silicon single crystal from the polycrystalline silicon material by a Czochralski method,

wherein said n-type silicon single crystal has a resistivity of about 10,000 Ωcm or more without addition of any dopant.

7. A polycrystalline silicon material according to claim 1 , wherein the n-type silicon single crystal is n-type on a top side and on a tail side of the single crystal.

8. A polycrystalline silicon material according to claim 1 , wherein the n-type silicon single crystal is n-type through an entire length of the single crystal.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (27)