TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The polycrystalline silicon ingot comprises continuous and large-sized monocrystalline silicon region, whose crystallographic orientation is same as the crystallographic orientation of the bottom of the seed crystal layer. The highly pure material is silicon sheet or highly pure quartz. The crystallographic orientation of seed crystal and monocrystalline silicon is (100), (110) or (111) orientation. The splicing and paving of large seed crystals having the same crystallographic orientation and regular geometrical shapes cover most of the regions above the isolative and protective layer during the process of forming the seed crystal layer, where gaps are present in between the large seed crystals. The large seed crystals are square or rectangular seed crystals. The shortest side of the large seed crystals is 100-160 mm. The width of the gaps between the large seed crystals, and the gaps between the large seed crystal and the bar-shaped seed crystal is 0-10 mm. The one side of the large seed crystal and the bar-shaped seed crystal is connected to the silicon raw material with a chamfer. The depth of the chamfer is 10-30 mm and the angle of the chamfer is less than 70 degrees . The thickness of the seed crystal layer is 10-30 mm. Preferred Method: The process of smelting the silicon raw material and parts of the seed crystal layer comprises heating the top and the sidewall of the container, keeping the temperature at the top of the container higher than the smelting point of the silicon and the temperature at the bottom of the container lower than the smelting point of the silicon to form a temperature gradient perpendicular to the bottom of the container, smelting the silicon raw material and parts of the seed crystal layer in the container from top to bottom, and keeping the seed crystal layer contacted with the isolative and protective layer in the solid state. The method further comprises keeping the solid-liquid interface parallel to the bottom of the container during the process of heating the container. The process of crystallizing the liquid layer comprises opening insulating bodies around the container, cooling the container by using a water cooling system to form the temperature gradient perpendicular to the bottom of the container, crystallizing the liquid layer, and slowly increasing the temperature of the container along the upward direction perpendicular to the bottom of the container. The process of smelting the silicon raw material and parts of the seed crystal layer further comprises filling inert gas in the concave grooves located on the baseboard during the process of smelting the seed crystal layer. The method comprises maintaining the temperature of the gaps between seed crystals above the concave groove more than the temperature at the other positions and maintaining the growth rate of the crystals in the gaps between the seed crystals lower than the crystals at the other positions during the process of crystallizing the liquid layer. The method comprises filling the bar-shaped seed crystals having the same crystallographic orientation as the large seed crystals in the region between the edge of the large seed crystal and the sidewall of the container when the large seed crystals can not completely cover the space above the isolative and protective layer. The process of loading the solid silicon raw material on the seed crystal layer comprises loading small granular silicon raw material and/or silicon powder on the seed crystal layer to fill the gaps between the seed crystals as well as fill the gaps between the seed crystal layer and the sidewall of the container and loading the silicon raw material of large volumes on the small granular silicon raw material and/or silicon powder.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The multiple crossed concave grooves are located on a baseboard arranged below the container in the polycrystalline silicon ingot growing furnace. The gaps between the seed crystals in the concave grooves and the container are located in the same vertical plane.