阅读说明：本技术 能够抑制电阻率反翘的重掺砷硅单晶生产方法 (Production method of heavily arsenic-doped silicon single crystal capable of inhibiting resistivity from warping ) 是由 闫龙 张兴茂 周文辉 李小红 伊冉 王忠保 于 2021-08-12 设计创作，主要内容包括：本发明提供一种能够抑制电阻率反翘的重掺砷硅单晶生产方法,属于硅单晶生产技术领域。通过统计分析,找到重掺砷硅单晶晶棒出现电阻率反翘率峰值处所对应的等径长度及该处影响电阻率反翘的特征因子,通过调整该特征因子,降低电阻率反翘率。例如,通过降低坩埚转速和/或提高单晶炉炉压,能够有效抑制重掺砷硅单晶晶棒电阻率反翘,提高产品合格率,减少浪费。(The invention provides a method for producing heavily arsenic-doped silicon single crystals capable of inhibiting resistivity from warping, and belongs to the technical field of silicon single crystal production. Through statistical analysis, the isodiametric length corresponding to the position of the monocrystalline ingot heavily doped with arsenic with the occurrence of the resistivity warp rate peak value and the characteristic factor influencing the resistivity warp at the position are found, and the resistivity warp rate is reduced by adjusting the characteristic factor. For example, the reverse tilting of the resistivity of the heavily arsenic-doped silicon single crystal rod can be effectively inhibited by reducing the rotating speed of the crucible and/or increasing the furnace pressure of the single crystal furnace, the product percent of pass is increased, and the waste is reduced.)

1. A production method of heavily-doped arsenic silicon single crystal capable of inhibiting electrical resistivity from warping is characterized in that in the isometric process of the heavily-doped arsenic silicon single crystal, characteristic factors influencing the electrical resistivity warping are adjusted at a target position to reduce the electrical resistivity warping rate; wherein the characteristic factors influencing the resistivity warping are confirmed by the following steps:

counting the equal-diameter length corresponding to the position of the peak value of the rate of reverse warping of the resistivity of a plurality of heavily arsenic-doped silicon single crystal bars, and calculating the average equal-diameter length;

obtaining a plurality of potential influence factors of a plurality of heavily arsenic-doped silicon single crystal bars at the average equal-diameter length and the resistivity warping rate of the heavily arsenic-doped silicon single crystal bars at the average equal-diameter length;

calculating the correlation degree of the resistivity warping rate and each potential influence factor, and sequencing the correlation degrees from large to small;

and taking one or two potential influence factors with the top rank of the correlation as characteristic factors influencing the resistivity warping.

2. The method for producing a heavily arsenic-doped silicon single crystal capable of suppressing resistivity reversion as claimed in claim 1, wherein the potential influencing factors include crucible rotation speed, single crystal furnace pressure, argon gas flow rate, single crystal growth speed, and temperature.

3. The method for producing the heavily arsenic-doped silicon single crystal capable of suppressing the reverse warping of resistivity as claimed in claim 1, wherein the step of "counting the equal diameter lengths corresponding to the positions of the peak values of the reverse warping rates of the resistivity of the several heavily arsenic-doped silicon single crystal ingots and calculating the average equal diameter length" is carried out by segmenting the heavily arsenic-doped silicon single crystal ingots, measuring the resistivity of each segment, and counting the equal diameter lengths corresponding to the positions of the peak values of the resistivity.

4. The method for producing the heavily arsenic-doped silicon single crystal capable of inhibiting resistivity turn-up as claimed in claim 1, wherein the step of calculating the correlation degree between the resistivity turn-up rate and each potential influence factor and sorting the correlation degrees from large to small is carried out by calculating the correlation coefficient between the resistivity turn-up rate and each potential influence factor by using a correlation coefficient analysis method and calculating the absolute value of the correlation coefficient as the correlation degree of each potential influence factor.

5. The method for producing a heavily arsenic-doped silicon single crystal capable of suppressing resistivity warp as claimed in claim 1, comprising the steps of:

obtaining an adjustment strategy of characteristic factors influencing the resistivity warping;

acquiring an adjusting time; wherein the adjusting time is (A-120) mm to (A-30) mm, and A is the average equal diameter length.

6. The method for producing a heavily arsenic-doped silicon single crystal capable of suppressing resistivity turn-up as claimed in claim 5, wherein:

when the determined characteristic factor influencing the electrical resistivity warping is the crucible rotating speed, the crucible rotating speed is reduced by 1-5 rpm so as to reduce the electrical resistivity warping rate;

and when the determined characteristic factors influencing the electrical resistivity warping are the crucible rotating speed and the single crystal furnace pressure, simultaneously, the crucible rotating speed is reduced down by 1 rpm-5 rpm, and the single crystal furnace pressure is increased up by 2 kPa-15 kPa so as to reduce the electrical resistivity warping rate.

Technical Field

The invention belongs to the technical field of silicon single crystal production, and particularly relates to a production method of heavily arsenic-doped silicon single crystal capable of inhibiting resistivity from warping.

Background

The heavily arsenic-doped monocrystalline silicon wafer is an ideal epitaxial substrate material. As arsenic has strong volatility, the resistivity of the heavily arsenic-doped single crystal is difficult to control accurately in the production process. When the volatilization of arsenic is greater than the segregation, the resistivity is high end to end (usually, the axial distribution of the resistivity of single crystal is low end to end due to the segregation effect), which we call the resistivity tilt. The reverse warping of the resistivity causes the resistivity of the heavily arsenic-doped silicon single crystal to exceed the specification requirement of the product, and causes excessive waste.

Disclosure of Invention

In view of this, the invention provides a method for producing heavily-doped arsenic silicon single crystal capable of inhibiting the resistivity from warping, so as to solve the technical problem of resistivity warping of heavily-doped arsenic silicon single crystal in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a heavily-doped arsenic silicon single crystal production method capable of inhibiting resistivity from warping is characterized in that in the isometric process of a heavily-doped arsenic silicon single crystal, characteristic factors influencing the resistivity warping are adjusted at a target position so as to reduce the resistivity warping rate; wherein the characteristic factors influencing the resistivity warping are confirmed by the following steps:

counting the equal-diameter length corresponding to the position of the peak value of the rate of reverse warping of the resistivity of a plurality of heavily arsenic-doped silicon single crystal bars, and calculating the average equal-diameter length;

obtaining a plurality of potential influence factors of a plurality of heavily arsenic-doped silicon single crystal bars at the average equal-diameter length and the resistivity warping rate of the heavily arsenic-doped silicon single crystal bars at the average equal-diameter length;

calculating the correlation degree of the resistivity warping rate and each potential influence factor, and sequencing the correlation degrees from large to small;

and taking one or two potential influence factors with the top rank of the correlation as characteristic factors influencing the resistivity warping.

Preferably, the potential influencing factors comprise crucible rotation speed, single crystal furnace pressure, argon flow, single crystal growth speed and temperature.

Preferably, in the step of counting the equal diameter length corresponding to the position of the peak value of the rate of reverse warping of the resistivity of a plurality of heavily arsenic-doped silicon single crystal bars and calculating the average equal diameter length, segmenting the heavily arsenic-doped silicon single crystal bars, measuring the resistivity of each segment, and counting the equal diameter length corresponding to the position of the peak value of the resistivity, wherein the length of each segment is 30-100 mm.

Preferably, in the step of calculating the correlation between the resistivity warp rate and each potential influence factor and sorting the correlation from large to small, a correlation coefficient analysis method is adopted to calculate the correlation coefficient between the resistivity warp rate and each potential influence factor and calculate the absolute value of the correlation coefficient to serve as the correlation of each potential influence factor.

Preferably, the method comprises the following steps:

obtaining an adjustment strategy of characteristic factors influencing the resistivity warping;

acquiring an adjusting time; wherein the adjusting time is (A-120) mm to (A-30) mm, and A is the average equal diameter length.

Preferably, when the determined characteristic factor influencing the electrical resistivity warping is the crucible rotating speed, the crucible rotating speed is reduced by 1-5 rpm so as to reduce the electrical resistivity warping rate;

and when the determined characteristic factors influencing the electrical resistivity warping are the crucible rotating speed and the single crystal furnace pressure, simultaneously, the crucible rotating speed is reduced down by 1 rpm-5 rpm, and the single crystal furnace pressure is increased up by 2 kPa-15 kPa so as to reduce the electrical resistivity warping rate.

According to the technical scheme, the invention provides the production method of the heavily arsenic-doped silicon single crystal capable of inhibiting the electrical resistivity from warping, and the production method has the beneficial effects that: through statistical analysis, the isodiametric length corresponding to the position of the monocrystalline ingot heavily doped with arsenic with the occurrence of the resistivity warp rate peak value and the characteristic factor influencing the resistivity warp at the position are found, and the resistivity warp rate is reduced by adjusting the characteristic factor. By taking the embodiment of the invention as an example, the reverse tilting of the resistivity of the heavily arsenic-doped silicon single crystal rod can be effectively inhibited by reducing the rotating speed of the crucible and/or increasing the furnace pressure of the single crystal furnace, the qualification rate of products is increased, and the waste is reduced.

Detailed Description

The technical solution and the technical effect of the embodiment of the present invention are further described in detail below.

In a specific embodiment, in the production method of the heavily-doped arsenic silicon single crystal capable of inhibiting the electrical resistivity from warping, characteristic factors influencing the electrical resistivity warping are adjusted at a target position in the isometric process of the heavily-doped arsenic silicon single crystal so as to reduce the electrical resistivity warping rate. Wherein the characteristic factors influencing the resistivity warping are confirmed by the following steps:

s01, counting the equal-diameter lengths corresponding to the positions of the peak values of the warping rates of the resistivities of the multiple heavily arsenic-doped silicon single crystal bars, and calculating the average equal-diameter length.

Generally, the electrical resistivity of the heavily arsenic-doped silicon single crystal ingot is inversely warped within the range of 400mm of the equal-diameter head, in order to more accurately obtain the peak value of the electrical resistivity of the heavily arsenic-doped silicon single crystal ingot, the head of the heavily arsenic-doped silicon single crystal ingot to be detected is further segmented, the length of each segment is 30 mm-100 mm, the electrical resistivity of each segment is measured, the position with the maximum electrical resistivity is found, and the equal-diameter length corresponding to the position with the maximum electrical resistivity is counted.

It is worth noting that the warpage rate = (resistivity at equal diameter 50 mm-resistivity at grade 250 mm)/resistivity at grade 50 mm. When the warpage rate is a negative value, the existence of warpage is indicated, the smaller the negative value is, the more serious the warpage is, when the warpage rate is a positive value, the warpage is not indicated, and the larger the positive value is, the more the resistivity is not warped.

S02, acquiring a plurality of potential influence factors of a plurality of heavily arsenic-doped silicon single crystal bars at the average equal diameter length and the electrical resistivity warping rate of the heavily arsenic-doped silicon single crystal bars at the average equal diameter length.

The potential influencing factors include but are not limited to crucible rotation speed, single crystal furnace pressure, argon flow, single crystal growth speed and temperature.

And S03, calculating the correlation between the resistivity warping rate and each potential influence factor, and sequencing the correlation from large to small.

Preferably, a correlation coefficient analysis method is adopted to calculate the correlation coefficient between the resistivity warping rate and each potential influence factor, and the absolute value of the correlation coefficient is obtained to be used as the correlation degree of each potential influence factor.

And S04, taking one or two potential influence factors with the top correlation rank as characteristic factors influencing the resistivity warping.

Namely, one or two potential influence factors with the highest correlation degree with the electrical resistivity warp rate of the heavily arsenic-doped silicon single crystal bar are selected as characteristic factors influencing the electrical resistivity warp. And adjusting one or two potential influence factors can obviously influence the electrical resistivity warping rate of the heavily arsenic-doped silicon single crystal bar.

As a preferred embodiment, the production method of the heavily arsenic-doped silicon single crystal capable of inhibiting the electrical resistivity from warping comprises the following steps:

and S10, obtaining an adjusting strategy of the characteristic factors influencing the resistivity warping.

After determining one or two characteristic factors influencing the electrical resistivity warpage of the heavily arsenic-doped silicon single crystal bar, according to the actual production condition, equipment and process state, under the condition of ensuring that other performance parameters (such as electrical resistivity, strength and the like) of the heavily arsenic-doped silicon single crystal bar are not changed essentially, adjusting the characteristic factors to reduce the electrical resistivity warpage rate.

S20, obtaining an adjusting time; wherein the adjusting time is (A-120) mm to (A-30) mm, and A is the average equal diameter length.

Namely, after the equal-diameter length corresponding to the reverse warping peak value of the resistivity of the heavily arsenic-doped silicon single crystal rod is determined, and after an adjusting scheme is determined, in practice, automatic adjustment is carried out through a single crystal furnace control system. In the adjusting process, the system acquires the data of the equal-diameter length in real time, and enters adjustment when the equal-diameter length reaches (A-120) mm to (A-30) mm, and the adjustment is finished when the equal-diameter length reaches A.

In one embodiment, when the determined characteristic factor affecting the resistivity warpage is the crucible rotation speed, the crucible rotation speed is adjusted down by 1rpm to 5rpm to reduce the resistivity warpage rate. Generally, in the process of constant diameter, the rotating speed of the crucible is 6 rpm-14 rpm, and practice shows that the lowering of the rotating speed of the crucible is beneficial to inhibiting the reverse warping of the resistivity of the heavily arsenic-doped silicon single crystal, but when the lowering of the rotating speed of the crucible is too large, the limit of the processing capability is reached, and the characteristic factor is continuously lowered, so that the crystallization is influenced.

And when the determined characteristic factors influencing the electrical resistivity warping are the crucible rotating speed and the single crystal furnace pressure, simultaneously, the crucible rotating speed is reduced down by 1 rpm-5 rpm, and the single crystal furnace pressure is increased up by 2 kPa-15 kPa so as to reduce the electrical resistivity warping rate.

The technical scheme and technical effects of the invention are further explained by the specific examples below. It is worth noting that the following specific experimental examples all adopt a Hanhong 2408SR single crystal furnace to produce 8 inches heavily arsenic-doped silicon single crystal with low resistivity (the resistivity target is 0.003 ohm. In the experimental examples of the present invention, the process parameters which are not particularly limited are generally parameters which can be obtained by those skilled in the art.

When the adjustment is not enhanced, in the same process of the following experimental examples, 2 batches (i.e. 20 crystal rods pulled in total) are produced by using 10 hanhong 2408SR single crystal furnaces arranged in parallel as the statistical background base.

Through data arrangement, the fact that the re-doped arsenic silicon single crystal resistivity is inversely warped within the range of 400mm of the head of the crystal bar is found, the specific position is unknown, so that the crystal bar with the resistivity of 0-400 mm is subdivided in the first step (each 30-100 mm is divided into 1 section), the area where the maximum value of the resistivity is inversely warped is found and concentrated at the position of 200-300 mm, and the average value (namely the average equal diameter length) is 250 mm.

Five variables of the crucible rotation speed, the single crystal furnace pressure, the argon flow, the single crystal growth speed and the temperature of the heavily arsenic-doped silicon single crystal bar at the equal diameter of 250mm and nearby are obtained and used as potential influence factors. And analyzing the correlation between the five variables and the electrical resistivity warping rate, and sequencing the correlation to obtain the great influence of the crucible rotation speed and the single crystal furnace pressure on the electrical resistivity warping of the heavily arsenic-doped silicon single crystal.

Comparative example 1

After the constant diameter process, the rotating speed of the crucible is kept at a (generally, a is more than or equal to 6 and less than or equal to 14) and the furnace pressure of the single crystal furnace is kept at b (generally, b is more than or equal to 8 and less than or equal to 24), and the statistical average resistivity warping rate is 7.9 percent until the constant diameter is finished.

Experimental examples one to four

Keeping the furnace pressure of the single crystal furnace as b, gradually reducing the rotation speed of the crucible to a-1, a-2, a-3 and a-4 respectively from the position where the furnace pressure enters the equal diameter of 150mm to the position where the furnace pressure ends at the equal diameter of 250mm until the equal diameter ends. Under the same other conditions as comparative example 1, the statistical average resistivity warpage rates are-6.1%, -5.6%, -3.2%, -1.5%, respectively.

Experimental example five to example eight

From the position of 150mm of the constant diameter to the position of 250mm of the constant diameter, gradually reducing the rotating speed of the crucible to a-4, and simultaneously increasing the furnace pressure of the single crystal furnace to b +3, b +7 and b +11 respectively until the end of the constant diameter. Under the same other conditions as in comparative example 1, the statistical average resistivity warping rates were-1.27%, 0.33%, and 1.4%, respectively.

It can be seen from the first to fourth embodiments that the rotation speed of the crucible is reduced at a position 150mm-250mm after the crucible enters the equal diameter, which is beneficial to inhibiting the reverse warping of the resistivity of the heavily arsenic-doped silicon single crystal. However, when the crucible rotation speed is reduced to a certain degree, the process capability limit is reached, and the crystallization is affected. At the moment, the furnace pressure of the single crystal furnace is increased in an auxiliary mode, the warping rate of the resistivity of the heavily arsenic-doped silicon single crystal is further adjusted, the qualified rate of products is increased, and waste is reduced.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.