Abstract: In a conventional method for pulling a single crystal, in order to exclude the dislocation induced in contact of a seed crystal with a melt, a neck having a small diameter has been formed. But when a heavy single crystal having a large diameter of 12 inches or so is pulled, it is impossible to hold the single crystal, leading to the falling. When the diameter of the neck is made larger in order to prevent the falling, the dislocation cannot be excluded, leading to the propagation of the dislocation to the single crystal. In the present invention, using a seed crystal having a cylindrical body and a conical front portion, the induction of the dislocation is inhibited by making the temperature of the front portion almost the same as the temperature of the melt when the front portion of the seed crystal is brought into contact with the melt and a single crystal is pulled without forming a neck after melting part of the front portion into the melt.

Abstract: A process for producing single crystals has been presented which enables the pulling up and growing of single crystals, without loss of accurate control of the oxygen concentration in the crystal, and with excellent dielectric strength of subsequently produced gate oxide films. The process of producing single crystals in accordance with this invention is characterized by confluence of the inert gas flows (33 and 32) once divided into outside and inside a heat resistant and heat insulative component (7).

Abstract: A silicon melting crucible having a double structure, in which a quartz crucible is inserted inside of a carbon crucible, is provided with devices for preventing deformation, such as turning-down, buckling and bending at an upper portion of the quartz crucible, or invasion of an SiO gas into a space between the quartz crucible and the carbon crucible during pulling up of a silicon single crystal. According to one form of the invention an upper portion of the quartz crucible has a frusto-conical inclined portion with an angle of inclination desirably of from 5.degree. to 40.degree.. According to another form of the invention a carbon ring having a cross section of either L-shape or U-shape is applied to the upper portion of the quartz crucible and the carbon crucible.

Abstract: Methods and apparatuses for pulling a single crystal. In a conventional method for pulling a single crystal, a neck having a smaller diameter has been formed in order to exclude dislocation induced in dipping a seed crystal into a melt. But in pulling a heavy single crystal having a large diameter of 12 inches or more, the single crystal cannot be supported and falls. When the diameter of the neck is large enough to prevent the fall, the dislocation can not be excluded and propagates to the single crystal. In the present invention, using an apparatus for pulling a single crystal having a laser beam generator or an incoherent light generating-inducing apparatus, the temperature of the front portion of the seed crystal is gradually raised by being irradiated with the laser beam or the incoherent light, and then, the seed crystal is dipped into the melt. As a result, the induction of the dislocation to the seed crystal caused by a thermal stress is prevented.

Abstract: A carrier box serving as a thin-plate supporting container includes a container body for defining therein a chamber for supporting and housing therein a plurality of semiconductor wafers and a lid for covering the container body. In one embodiment, the carrier box includes an internal-pressure adjusting mechanism for maintaining the internal pressure in the chamber at the same level as that of the external pressure against the chamber. The internal-pressure adjusting mechanism is composed of an opening formed in a wall of the container body or the like, and a filter detachably mounted in the opening for removing foreign matters while allowing gas to easily enter and exit the chamber so as to maintain the chamber in a clean state. In another embodiment, the carrier box includes a gasket made of a porous material or the like.

Abstract: A process of growing crystals in which the uniformity of the oxygen concentration is desirable. In the process, the upper part of the material in the crucible is heated to form a molten layer, and a solid layer is formed at its lower part, then a seed crystal is made to contact the surface of the molten layer, and pulled up to grow a crystal, while characteristically a magnetic field is applied to the molten layer. This method produces single crystals with a uniform distribution of oxygen concentration. Furthermore, this method produces single crystals at low cost and with a high productivity.

Abstract: The present invention provides a method for producing high-purity titanium from titanium sponge obtained by the Kroll process in which a core of the cylindrical lump of titanium sponge obtained with a weight less than 20-30% of that of the cylindrical lump is separated by cutting off from the lump a bottom portion, a top portion and a peripheral portion, and the core is cut by a press into grains of specific size, which are melted into ingot or refined by reaction with iodine. The high-purity titanium thus produced contains less than 300 ppm of oxygen and less than 10 ppm each of iron, nickel, chromium, aluminum and silicon, the balance being titanium and inevitable impurities; or less than 200 ppm of oxygen and less than 1 ppm each of iron, nickel, chromium, aluminum and silicon, the balance being titanium and inevitable impurities. Thus the invention provides titanium materials of very high purity suitable for thin film deposition as wiring of LSIs from titanium sponge obtained by the Kroll process.

Abstract: A semiconductor wafer cleaning liquid includes an aqueous hydrogen fluoride (HF) solution having a HF concentration between 0.03% and 0.05% by weight, which is adjusted to 20.degree. C. or below and into which ozone is directly dissolved up to a saturation point. A method for cleaning semiconductor wafers incudes the steps of charging an aqueous HF solution adjusted to 20.degree. C. or below and having an HF concentration between 0.03% and 0.05% by weight into a treatment bath; dissolving ozone into the aqueous solution up to a saturation point to prepare a cleaning liquid; dipping to etch semiconductor substrate into the cleaning liquid in the treatment bath; and rinsing the semiconductor substrate with pure or ozone-dissolved water in a bath separate from the treatment bath.

Abstract: A device for producing single crystals has been presented which enables the pulling up and growing of single crystals. Without loss of accurate control of the oxygen concentration in the crystal, and with excellent dielectric strength of subsequently produced gate oxide films. A heat resistant and heat insulating component (7) of cylindrical or cylinder-like form surrounding the pulling up zone of the single crystal is suspended from the ceiling (6a) or the upper part of the wall of the metallic vessel (6) with a gap (h.sub.1) from the ceiling to divide the inert gas (30) supplied from above into inert gas flows (33 and 32) outside and inside this component.

Abstract: When a Si single crystal 8 is pulled up from a melt 6 received in a crucible 2, the state of eddy flows generated in the melt 6 is judged from the temperature distribution of the melt at the surface. According to the result of judgement, the gas, i.e. N.sub.2, Xe or Kr, which causes extraoridnary deviation in the density of a melt 6 is added to an atmospheric gas, so as to keep the eddy flows under unstabilized condition. The effect of said gas is typical in the case of crystal growth from the melt to which a dopant such as Ca, Sb, Al, As or In having the effect to suppress the extraordinary deviation in the density is added. Since the single crystal is pulled up from the melt held in the temperature-controlled condition at the surface, impurity distribution and oxygen distribution are made uniform along the direction of crystal growth. A single crystal obtained in this way has highly-stabilized quality.

Abstract: When a B or P-doped Si single crystal is pulled up from a B or P-doped melt by the Czochralski method, an element such as Ga, Sb or In having the effect to reduce the heat expansion coefficient of said melt at a temperature near the melting point is added to said melt. The additive element stabilizes the temperature condition of crystal growth so as to control the generation of eddy flows just below the interface of crystal growth.When a Ga or Sb-doped Si single crystal is pulled up from a Ga or Sb-doped melt, an element such as B or P having the effect to increase the heat expansion coefficient of said melt at a temperature near the melting point is added. The agitation of the melt just below the interface of crystal growth is accelerated by the addition of B or P, so as to assure the growth of a Si single crystal from the melt having impurity distribution made uniform along the radial direction.

Abstract: A process for producing single crystals with little OSF generation and excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the silicon single crystal in the direction of pulling. The process is carried out with an apparatus including a crucible which contains the melt of the single crystal material, a heating element which heats the melt, a pulling shaft to grow the single crystal, a protective gas inlet pipe, and a chamber which contains all above mentioned components. In addition, the apparatus is provided with a circular cylinder or a conical shaped heat resistant and heat insulating component below the protective gas inlet pipe.

Abstract: When a single crystal is pulled up from a melt, the difference .DELTA.T between temperatures at the bottom of a crucible and at the interface of crystal growth is controlled so as to hold the Rayleigh constant defined by the formula of:R a=g.multidot..beta..multidot..DELTA.T.multidot.L/.kappa..multidot..nu.within the range of 5.times.10.sup.5 -4.times.10.sup.7, wherein g represents the acceleration of gravity, .beta. the volumetric expansion coefficient of the melt, L the depth of the melt, .kappa. thermal diffusivity and .nu. the kinematic viscocity. Since the convection mode of the melt at the interface of crystal growth is constantly held in the region of soft turbulence, a single crystal is grown under the stabilized temperature condition without the transfer of the impurity distribution in the melt into the growing single crystal.

Abstract: A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.

Abstract: This invention relates to the apparatus and the process for producing single crystals with little OSF generation and excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the silicon single crystal in the direction of pulling. The apparatus is provided with a crucible which contains the melt of the single crystal material, a heating element which heats the melt, a pulling shaft to grow the single crystal, a protective gas inlet pipe, and a chamber which contains all above mentioned components. In addition, the apparatus is provided with a circular cylinder or a cylindrical shaped heat resistant and heat insulating component below the protective gas inlet pipe noted above.

Abstract: An apparatus for producing a single crystal comprising a heater which is arranged on the outer periphery of a crucible and movable along the axis of growth of a single crystal. The heater is moved along the direction of growth of the single crystal in accordance with the surface position of the molten liquid layer in the crucible. The apparatus for producing a single crystal further comprising means for adjusting the speed at which the seed crystal is pulled. For example, the pulling speed of the seed crystal is adjusted in accordance with the position of the heater.

Abstract: The present invention provides a method of manufacturing a semiconductor wafer whereby (1) deterioration of a micro-roughness in a low temperature range in hydrogen atmospheric treatment and increase of resistivity due to outward diffusion of an electrically active impurity in a high temperature range are prevented; (2) in the heat treatment in a hydrogen gas atmosphere, the concentration of gas molecules in the atmosphere, such as water, oxygen and the like, are brought to 5 ppm or less in water molecule conversion; and a reaction is suppressed in which a substrate surface is oxidized unequally and the micro-roughness deteriorates; and (3) the same kind of impurity as the electrically active impurity contained in a Si substrate is mixed into the atmosphere and the outward diffusion of the impurity in the vicinity of the Si substrate surface is prevented to prevent variation of the resistivity.

Abstract: A solid layer is melted from the upper part thereof by the heat of a heater while the contact area between a molten liquid layer and an inner wall of a crucible is adjusted in a Double Layered CZ method, so that the eluting amount of oxygen from the crucible to the molten liquid layer is controlled. Accordingly, silicon single crystals of the low concentration of oxygen are produced.

Abstract: A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.

Abstract: A method for growing silicon single crystal uses as materials, silicon granules prepared by the silane process and having a residual hydrogen concentration of 7.5 wtppm or less, silicon granules prepared by the trichlorosilane process and having a residual chlorine concentration of 15 wtppm or less. In the case where such silicon granules are used, a bursting phenomenon does not occur when the silicon granules are melted. As a result, there is no scattered matter due to the bursting phenomenon, whereby the growth condition of the single crystal is not disturbed.