Methods for preparing epitaxial wafers are disclosed. The methods may involve control of the (i) a growth velocity, v, and/or (ii) an axial temperature gradient, G, during the growth of an ingot segment such that v/G is less than a critical v/G. An epitaxial layer is deposited on a substrate sliced from the silicon ingot.

Provided is a heat shielding member, a single crystal pulling apparatus, and a method of producing a single crystal silicon ingot, which can expand the margin of the crystal pulling rate with which a defect-free single crystal silicon can be obtained. A heat shielding member is provided in a single crystal pulling apparatus, the heat shielding member including a cylindrical tubular portion surrounding an outer circumferential surface of the single crystal silicon ingot; and a ring-shaped projecting portion under the tubular portion. The projecting portion has an upper wall, a bottom wall, and two vertical walls, a heat insulating material with a ring shape is provided in the space surrounded by those walls; and a gap between the vertical wall adjacent to the single crystal silicon ingot and the heat insulating material.

A method for producing Si ingot single crystal including a Si ingot single crystal growing step, a temperature gradient controlling step and a continuous growing step is provided. In the growing step, the Si ingot single crystal is grown in silicon melt in crucible, and the growing step includes providing a low-temperature region in the Si melt and providing a silicon seed to contact the melt surface of the silicon melt to start crystal growth, and silicon single crystal grows along the melt surface of the silicon melt and toward the inside of the silicon melt. In the temperature gradient controlling step, the under-surface temperature gradient of the silicon single crystal is G1, the above-surface temperature gradient of the silicon single crystal is G2, G1 and G2 satisfy: G2/G1<6. The step of controlling the temperature gradient of silicon single crystal is repeated to obtain the Si ingot single crystal.

The disclosure discloses a method and a system for controlling temperature during crystal growth. The method includes that: the power of each of the heaters is constantly adjusted and simulating is performed by software to calculate the thermal field correspondingly at a solid-liquid interface and vicinity of the solid-liquid interface; the thermal field is coupled with a moving grid to determine whether the solid-liquid interface and the total thermal energy both reach thermal equilibrium; the power of each of the heaters that enables both the solid-liquid interface and the total thermal energy to reach the thermal equilibrium is stored and a thermal equilibrium diagram is drawn based on the power of each of the heaters; and during crystal growth, the power of each of the heaters is selected from the thermal equilibrium diagram which is drawn to control the temperature gradient at the solid-liquid interface.

The invention provides a method of detecting crystallographic defects, comprising: sampling wafer of an ingot in complying with a predetermined wafer sampling frequency; identifying crystallographic defects of the wafer to show the crystallographic defects of the wafer; characterizing observation of the crystallographic defects of the wafer and extracting a value characterizing the crystallographic defects; through a result of characterizing the crystallographic defects, obtaining a radial distribution of density of the wafer and categorizing the crystallographic defects; and obtaining an isogram of the crystallographic defects of the wafer to show a crystallographic defect distribution of the whole ingot according to the value characterizing the crystallographic defects and categories of the crystallographic defects. It is no need to break the ingot to obtain the crystallographic defect distribution of the whole ingot, through which the technology for growing the ingot may be effectively adjusted to obtain the ingot with required characteristics of defect.

An embodiment provides a method for growing a silicon single crystalline ingot that may include: preparing a silicon melt solution in a crucible; probing a seed in the silicon melt solution; rotating the seed and the crucible while applying a horizontal magnetic field to the crucible; and pulling up an ingot grown from the silicon melt solution, wherein an interface between the growing ingot and the silicon melt solution is formed downward from a horizontal plane at 1 to 5 millimeters, and a bulk micro defects (BMD) size of the grown ingot is between 55 and 65 nanometers.

A method for growing a single crystal silicon ingot by the continuous Czochralski method is disclosed. The melt depth and thermal conditions are constant during growth because the silicon melt is continuously replenished as it is consumed, and the crucible location is fixed. The critical v/G is determined by the hot zone configuration, and the continuous replenishment of silicon to the melt during growth enables growth of the ingot at a constant pull rate consistent with the critical v/G during growth of a substantial portion of the main body of the ingot. The continuous replenishment of silicon is accompanied by periodic or continuous nitrogen addition to the melt to result in a nitrogen doped ingot.

A method for growing a single crystal silicon ingot by the continuous Czochralski method is disclosed. The melt depth and thermal conditions are constant during growth because the silicon melt is continuously replenished as it is consumed, and the crucible location is fixed. The critical v/G is determined by the hot zone configuration, and the continuous replenishment of silicon to the melt during growth enables growth of the ingot at a constant pull rate consistent with the critical v/G during growth of a substantial portion of the main body of the ingot. The continuous replenishment of silicon is accompanied by periodic or continuous nitrogen addition to the melt to result in a nitrogen doped ingot.

A method for producing a single crystal includes: bringing a seed crystal into contact with a dopant-added melt, in which a red phosphorus is added to a silicon melt, such that a resistivity of the single crystal is 0.9 mΩ.Math.cm or less and subsequently pulling up the seed crystal, to form a straight body of the single crystal; and withdrawing the single crystal from the dopant-added melt in a state that a temperature of an upper end of the straight body is 590 degrees C. or more.

A method of producing silicon single crystal ingot by pulling the silicon single crystal ingot made of an N-region by the CZ method, including: performing an EOSF inspection including a heat treatment to manifest oxide precipitates and selective etching on sample wafer from the silicon single crystal ingot composed of the N-region to measure a density of EOSF; performing a shallow-pit inspection to investigate a pattern of occurrence of a shallow pit; adjusting the pulling conditions according to result of identification of a defect region of the sample wafer by the EOSF and shallow-pit inspections to pull a next silicon single crystal ingot composed of the N-region, wherein in the identification of the defect region, for an N-region, what portion of an Nv-region or Ni-region the defect region corresponds to is also identified.