Method for measuring point defect distribution of silicon single crystal ingot

A method for measuring the point defect distribution of a silicon single crystal ingot, comprising

• (a3) a step of preparing a sample for measurement including regions M, [Pv], [Pi] and [I] by cutting to an axial direction a p-type silicon single crystal ingot which is pulled up by changing a pulling-up speed from silicon melt doped with boron,
• (b3) a step of coating a transition metal solution dissolving a transition metal M at a concentration of 1 to 1000 ppm on the surface of the sample to stain the sample with the metal,
• (c3) a diffusion thermal treatment step of rapidly charging the sample stained with the metal into a thermally treating furnace which is retained at a first temperature of 600° C. to 900° C., under argon, nitrogen, oxygen, hydrogen or mixed gas atmosphere thereof, thereby rapidly heating the sample at a temperature raising speed of 3.3° C./min. or more to thermally treat the sample for 0.5 hour to 4 hours, rapidly cooling the sample at a temperature cooling speed of 3.3° C./min. or more by rapidly taking out the sample from the thermally treating furnace and diffusing the transition metal M which is coated on the surface of the sample into the inside of the sample,
• (d3) a silicide forming thermal treatment step of rapidly charging the sample into a thermally treating furnace which is retained at a second temperature of 450° C. to 550° C. lower than the first temperature by 150° C. to 450° C., under argon, nitrogen, oxygen, hydrogen or mixed gas atmosphere thereof, thereby rapidly heating the sample at a temperature raising speed of 3.3° C./min. or more to thermally treat the sample for 0.5 hour to 4 hours, rapidly cooling the sample at a temperature cooling speed of 3.3° C./min. or more by rapidly taking out the sample from the thermally treating furnace and forming metal silicide from the transition metal M which is diffused into the inside of the sample,
• (e3) a dissolution thermal treatment step of rapidly charging the sample into a thermally treating furnace which is retained at a third temperature of 900° C. to 1100° C. higher than the second temperature by 450° C. to 550° C., under argon, nitrogen, oxygen, hydrogen or mixed gas atmosphere thereof, thereby rapidly heating the sample at a temperature raising speed of 3.3° C./min. or more to thermally treat the sample for 0.5 hour to 4 hours, rapidly cooling the sample at a temperature cooling speed of 3.3° C./min. or more by rapidly taking out the sample from the thermally treating furnace and dissolving the metal silicide which is formed in the inside of the sample,
• (f3) a step of measuring the concentration of the recombination center which the transition metal M forms in the whole sample which undergoes the dissolution thermal treatment and determining a correlation function from the measurement result,
• (g3) a step of measuring the diffusion length of minor carrier in the whole sample which undergoes the dissolution thermal treatment,
• (h3) a step of injecting heat or optical energy in the sample,
• (i3) a step of measuring the diffusion length of minor carrier in the whole sample in which the heat or optical energy is injected,
• (j3) a step of determining the difference of the diffusion lengths of minor carrier from the measurement result of the step (g3) and the measurement result of the step (i3), and
• (k3) a step of specifying the regions [Pv] and [Pi] in the sample and boundary thereof from the correlation function obtained in the step (f3) and the difference of the diffusion lengths of minor carrier obtained from the step (j3).
• Provided that the region [V] is a region having defects where the vacancy type point defect is dominant and excessively saturated vacancies are agglomerated, the region [Pv] is a region having defects where the vacancy type point defect is dominant and vacancies are not agglomerated, the region [Pi] is a region having defects where the interstitial silicon type point defect is dominant and interstitial silicons are not agglomerated, and the region [I] is a region having defects where the interstitial silicon type point defect is dominant and interstitial silicons are agglomerated.