30results about How to "Improve resistivity uniformity" patented technology

The invention discloses a method for improving the uniformity of axial resistivity of czochralski silicon. The method comprises the steps as follows: (1) melting a polycrystalline silicon raw material and a solid doping agent in an argon atmosphere to obtain stable molten silicon; (2) introducing seed crystals into the stable molten silicon, and conducting constant diameter growth on the crystals after necking and shouldering processes; and (3) during the constant diameter growth period, adding dopant gas with the conductive type opposite to that of the solid doping agent until the growth of the czochralski silicon is fulfilled. According to the method, the type and the usage amount of the dopant gas are convenient to control, various required impurity concentration distributions can be obtained, the utilization rate of the czochralski silicon is increased, and the uniformity of the resistivity of the czochralski silicon is remarkably improved.

The invention discloses a control method for an external extension transition section on a heavy doping arsenic underlay, which adopts chemical vapor deposition technology to grow light doping thin silicon extension layer at two times on a n-type heavy doping arsenic silicon underlay. After the growing of a first own extension layer, reduce the temperature to 870 to 930 DEG C. and take it out. During the process, remove the memory effect by putting in a HCI erosion base. After the completion of erosion, place the piece in furnace under the temperature of 870 to 930 DEG C. and then grow the residual extension layer. By checking and comparing the extension layer made with ordinary method and the method in the invention via an extension resistance analyzer, it is proved that the extension layer made of the method in the invention has steepy transition section and resistance of the extension layer has excellent evenness.

The invention relates to a method for growth of a SiC crystal for an off-axis substrate and a method for preparing an N type SiC substrate with high electric uniformity. A deviating SiC seed crystal is adopted, a mechanism of controlling facet growth by a seed crystal asymmetric bonding way is used, and a SiC single-crystal material having the diameter increased by 20 mm than a standard diameter is obtained through an atmosphere guide plate. The asymmetrical rounding work is performed, and the SiC single-crystal material without facets is obtained. The N type SiC single-crystal substrate material with low defect density and electrical deviation of 3.5% or less can be obtained by the method.

The invention provides a method for improving the uniformity of the electrical resistivity of an epitaxial layer. According to the method for improving the uniformity of the electrical resistivity of the epitaxial layer, pre-covering is conducted inside a cavity with a selected dopant according to the distribution condition of the electrical resistivity of the epitaxial layer grown on a test sample, namely, a film containing the dopant is grown inside the cavity, and then epitaxy processing is conducted on a substrate. In the epitaxy process, the dopant on the internal side wall of the pre-covered cavity and a base can be diffused out under the influence of high temperature, and thus the concentration of the dopant gas on the edge of the substrate can be changed; the dopant gas enters the epitaxial layer, the distribution of the electrical resistivity of the epitaxial layer is changed, the influence of doping on the uniformity of the electrical resistivity of the epitaxial layer is reduced, and the qualified rate of products is increased.

A thin film transistor substrate includes a base substrate, an active pattern, a gate insulation pattern and a gate electrode. The active pattern is disposed on the base substrate. The active pattern includes a source electrode, a drain electrode, and a channel disposed between the source electrode and the drain electrode. The gate insulation pattern and the gate electrode overlap with the channel. The gate insulation pattern is disposed between the channel and the gate electrode. The source electrode and the drain electrode each include a fluorine deposition layer.

The invention provides a coil structure for improving the zone-melting radial resistivity uniformity. The coil structure comprises a coil main body, a cooling water pipeline, a main seam, a plurality of sub seams and a plurality of transverse seams, wherein the coil main body is a flat plate coil; the upper surface of the coil main body is sunken into the inside of the coil into a centrosymmetric step structure; a coil hole is formed in the geometric center part of the coil main body; the cooling water pipeline is positioned inside a step at the outermost layer of the coil main body; the main seam is arranged on the coil main body in the radial direction and penetrates through the upper surface and the lower surface of the coil main body; the plurality of sub seams are arranged on the step surface at the innermost layer of the coil main body and penetrate through the upper surface and the lower surface of the step surface; the transverse seams are partially or all arranged on the sub seams; the transverse seams are perpendicular to the respective sub seam. The coil structure for improving the zone-melting radial resistivity uniformity has the advantage that due to the adaption of the technical scheme, the zone-melting silicon single-crystal radial resistivity uniformity can be simultaneously improved.

The invention discloses a method for suppressing the formation of carbon inclusion defects in the growth of conductive silicon carbide crystals. It uses carbon powder, silicon powder and nitrogen as raw materials to synthesize nitrogen-containing silicon carbide powder, and then uses the nitrogen-containing silicon carbide powder as raw material to grow silicon carbide single crystals to obtain silicon carbide crystals. The invention uses nitrogen-containing silicon carbide powder to grow silicon carbide crystals, which can make nitrogen doping more evenly distributed in the gas phase components, so that the resistivity uniformity in the wafer is better, and solves the problem that nitrogen gas cannot permeate due to nitrogen gas being introduced from the outside. Uniformity, resulting in poor uniformity of N doping concentration in the wafer, which in turn leads to poor uniformity of wafer resistivity. Therefore, the method for suppressing carbon inclusion defects in conductive silicon carbide crystals provided by the present invention is suitable for growing conductive silicon carbide crystals, especially suitable for preparing large-diameter conductive silicon carbide crystals, and has broad market application prospects.

The invention relates to a preparation method for a doped float zone silicon crystal. The method comprises that: (1) cone grinding, corrosion, cleaning and drying are performed on a polysilicon material; (2) the polysilicon material is fixed in a cavity of a magnetron sputtering apparatus, a phosphorus-silicon-doped target is arranged, vacuumizing is performed to achieve 5*10<-3> Pa, argon gas is introduced to achieve the pressure in the cavity of 1 Pa, a high voltage of 500 Kv is applied between the two electrodes, argon ions produced through ionization continuously bombard the target, the phosphorus atoms and the silicon atoms in the target obtain energy, sputter, and deposit on the surface of the polysilicon to form a layer of a uniform and compact phosphorus / silicon film, the sputtering is performed for 30-90 min and then is stopped, the sputtering chamber is opened to rotate the polysilicon 180 DEG, the steps are repeated, and the sputtering is continuously performed for the same time; and (3) the polysilicon material is taken out and placed into a float zone silicon crystal furnace, the seed crystal and the polysilicon are centered, steps of vacuumizing, argon gas introduction, preheating, fusion splicing, narrow neck shrinking and crystal diameter achieving are sequentially performed until the equal diameter is maintained, and the ending step is performed. The preparation method has characteristics of low-cost, high production efficiency and no toxicity and harm, wherein the uniformities of the radial resistivity and the axial resistivity are good.