36results about How to "Uniform doping concentration" patented technology

The invention discloses a method for enhancing the reliability of an SONOS (Silicon Oxide Nitride Oxide Semiconductor) flash memory device by means of selective epitaxy, which comprises the following steps: step 1, growing an epitaxial doping layer on a silicon substrate by adopting a selective epitaxial process; step 2, growing a tunneling oxidation layer on the epitaxial doping layer; step 3, growing a silicon oxynitride trap layer on the tunneling oxidation layer, and simultaneously carrying out in-situ doping on the silicon oxynitride trap layer by using N2O to form a silicon oxynitride mixture to serve as a medium for storing charges; and step 4, growing a high-temperature thermal-oxidation layer on the silicon oxynitride trap layer. In the method disclosed by the invention, an erasing voltage is regulated by means of selective epitaxial doping growth instead of ion implantation so as to avoid the damage to a silicon surface, thus the reliability of the SONOS flash memory device is improved and the service life of the SONOS flash memory device is prolonged.

This patent application discloses an LDMOS device and a manufacturing method thereof. The manufacturing method includes: forming an epitaxial layer over a substrate, implanting a drift region and a well region in the epitaxial layer; forming a gate structure over part of the well region; A first mask with a first opening is formed above the epitaxial layer, and an inversion region is formed by implanting at an oblique angle of the first opening. The inversion region is doped opposite to the drain region in the drift region and is symmetrical about the drain region. At the same time, An additional doping region of the same doping type as the well region is formed in the well region through the second opening of the first mask; then the source region and the drain region are also doped in the first opening and the second opening. The advantage of this patent is that the same mask is used to form the drain region, the inversion region in the drift region, and the additional doping region in the well region with the same doping concentration as the well region, which can not only effectively increase the breakdown voltage of the device, but also reduce the The on-resistance of the device is improved, and the self-protection capability of the device is improved without adding any additional cost.

The invention discloses a semiconductor structure forming method. The method comprises steps: a substrate with a first area and an adjacent second area is provided, wherein the surface of the substrate in the first area is provided with a first fin part and an adjacent second fin part, the surface of the substrate is provided with an isolation layer, and the minimal distance between the side wall of the first fin part and the side wall of the second fin part is a first distance; a mask layer is formed on the surface of the isolation layer, wherein an opening for enabling the first area to be exposed is arranged in the mask layer, the opening is provided with a first side wall and an opposite second side wall, the minimal distance between the side wall of the first fin part and the first side wall is larger than the minimal distance between the side wall of the second fin part and the first side wall, and the value obtained by dividing the thickness of the mask layer by the minimal distance between the side wall of the first fin part and the first side wall is larger than that obtained by dividing the distance between the top of the second fin part and the surface of the isolation layer by the first distance; and first lightly-doped injection with a first injection angle is carried out on the first fin part from one side of the first side wall, wherein the tangent value of the first injection angle is smaller than or equal to the value obtained of dividing the thickness of the mask layer by the second distance. The formed semiconductor structure is stable in performance.

A manufacturing method of a rare earth-doped optical fiber preformed rod relates to the field of optical fiber preformed rods, and comprises the following steps: S1, mounting a cylindrical rare earth material preformed target rod at a gas inlet end in a quartz glass substrate tube, mounting the substrate tube on a chemical vapor deposition device; S2, focusing laser on the rare earth material preformed target rod, introducing mixed gas composed of oxygen, chlorine, silicon tetrachloride gas, germanium tetrachloride gas, and carbides of fluorine, performing deposition to form an optical fiber core rod preform; S3, melting the optical fiber core rod preform for contraction at a high temperature to form the transparent optical fiber preformed rod. The method increases the diameter of the optical fiber preformed rod, greatly improves the production manufacturing efficiency and the rare earth ion doping uniformity of the rare earth-doped optical fiber preformed rod, reduces the content of ineffective impurities of the optical fiber preformed rod, also reduces the production cost, and is suitable for popularization of large-scale production.

The invention discloses a process for preparing a crystalline silicon solar cell by a solution method. The method comprises the steps: adding ethyl alcohol, polyethylene glycol, vinyltrimethoxysilaneand the like into a phosphoric acid solution to serve as a phosphorus diffusion solution source, and uniformly coating the surface of a silicon wafer with diffusion liquid through an ultrasonic atomization spraying method; then diffusing phosphorus at the high temperature to obtain the uniform doping concentration of the surface. According to the invention, the solution spraying method is adoptedto prepare a titanium dioxide anti-reflection film to replace a silicon nitride anti-reflection film prepared by a PECVD method, and a microemulsion composed of anionic polyacrylamide (APAM), isopropanol and the like is added into a titanium tetrachloride solution to serve as a precursor solution of the titanium dioxide film, so that the passivation function of the film on the silicon surface is improved.