50 results about "Cz silicon" patented technology

The present invention is directed to a single crystal Czochralski-type silicon wafer, and a process for the preparation thereof, which has at least a surface layer of high resistivity, the layer having an interstitial oxygen content which renders it incapable of forming thermal donors in an amount sufficient to affect resistivity upon being subjected to a conventional semiconductor device manufacturing process. The present invention further directed to a silicon on insulator structure derived from such a wafer.

The present invention generally relates to a high resistivity CZ silicon wafer, or a high resistivity silicon structure derived therefrom, and a process for the preparation thereof. In particular, the high resistivity silicon structure comprises a large diameter CZ silicon wafer as the substrate thereof, wherein the resistivity of the substrate wafer is decoupled from the concentration of acceptor atoms (e.g., boron) therein, the resistivity of the substrate being substantially greater than the resistivity as calculated based on the concentration of said acceptor atoms therein.

The invention discloses a control system of a high frequency switching power supply for a Cz silicon single crystal furnace and a control method. The control method includes the steps of combining self-adaptive fuzzy control and sliding mode variable structure control, and aiming at a high-frequency switch heating electric power for the Cz silicon single crystal furnace to design a power controller based on a self-adaptive fuzzy control and sliding mode variable structure control method. The control system of the high frequency switching power supply for the Cz silicon single crystal furnace and the control method play respective advantages of fuzzy control and sliding mode variable structure control, further improve dynamic performance of the system, have good robustness for input voltage or load disturbance, and relieve or avoid vibration which generally happens to a sliding mode.

Nitrogen-doped CZ silicon crystal ingots and wafers sliced therefrom are disclosed that provide for post epitaxial thermally treated wafers having oxygen precipitate density and size that are substantially uniformly distributed radially and exhibit the lack of a significant edge effect. Methods for producing such CZ silicon crystal ingots are also provided by controlling the pull rate from molten silicon, the temperature gradient and the nitrogen concentration. Methods for simulating the radial bulk micro defect size distribution, radial bulk micro defect density distribution and oxygen precipitation density distribution of post epitaxial thermally treated wafers sliced from nitrogen-doped CZ silicon crystals are also provided.

The automatic temperature adjustment method for Czochralski silicon single crystal disclosed by the present invention is used for automatic adjustment of the liquid surface temperature, comprising the following steps: setting the target liquid surface temperature value Ts, measuring the actual liquid surface temperature value T, and taking t as the fixed cycle time Calculate the difference ΔT between the actual liquid surface temperature T and the target liquid surface temperature Ts; judge whether ΔT is within a given range; if yes, enter the temperature stabilization process, if not, perform the temperature adjustment process; The value ΔT is calculated to obtain the power adjustment amount ΔPower and the power setting value Pr, the output power setting value Pr, and then adjust the temperature of the silicon melt surface. The present invention cancels the control that SP participates in, eliminates unstable factors, improves the stability of the system control temperature, improves the uniformity of temperature adjustment, improves the yield and reduces the production cost.

The invention discloses a crystal seeding method for Czochralski silicon single crystal. The seeding temperature is regulated by the seeding speed deviation, and the seeding speed deviation is the difference between the average seeding speed and the set seeding speed in the seeding temperature adjustment period. . If the seeding speed deviation is positive, the seeding temperature is fine-tuned positively; if the seeding speed deviation is negative, the seeding temperature is fine-tuned negatively. According to the difference in the diameter reduction process, the seeding temperature control methods include: the entire seeding process has only one continuous diameter reduction process, which is regulated throughout the process, and the seeding temperature fine-tuning amount is set according to the power adjustment coefficient; or the seeding process is a non-continuous process. The diameter reduction process includes the first diameter reduction process, the equal grain reduction process and the second diameter reduction process. After the second diameter reduction process, the target diameter of diameter reduction is achieved. During the equal grain reduction process, the seeding temperature is adjusted once. The amount of fine adjustment is set according to the power adjustment coefficient. The invention also discloses the production method of the Czochralski silicon single crystal adopting the above seeding method. The invention can accurately regulate the temperature of the seeded crystal, thereby improving the yield of single crystal.

In the present invention, as a bag to store polycrystalline silicon ingots, there is used a bag in which the concentration of paraffinic hydrocarbons in a concentrate of solvent-soluble components obtained by Soxhlet extraction using acetone as a solvent is lower than 300 ppmw as a value measured by GC-MS method; the concentration of antioxidants, lower than 10 ppmw; the concentration of ultraviolet absorbents, lower than 5 ppmw; and the concentration of antistatic agents and surfactants, lower than 50 ppmw. Then, when the polycrystalline silicon ingots are packed, preferably, the polycrystalline silicon ingots are put in the storage bag; thereafter, the storage bag is sealed; further, the storage bag is put and sealed in a linear low-density polyethylene bag containing an antistatic agent or a surfactant added in the bag material.