Stepped gradient epitaxial deep groove super junction and preparation method thereof

• Main Authors: WANG JINXIONG, ZHANG SHENGKAI, LIU CONGNING, BAI ZONGWEI
• Format: Patent
• Language: Chinese; English
• Published: 22.11.2022
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

The invention discloses a stepped gradient epitaxial deep groove super junction and a preparation method thereof. Relates to a semiconductor integrated circuit manufacturing method. Comprising the following steps: providing a uniformly doped epitaxial layer, and forming a step-shaped groove in the epitaxial layer by adopting a photoetching process; the step-shaped groove is prepared by the following sub-steps of: etching a first groove in an epitaxial layer by adopting a photoetching process; etching a second groove in the first groove, wherein the width of the second groove is not greater than that of the first groove; the step-shaped groove is filled with polycrystalline silicon, and the method comprises the following steps that the second groove is filled with a second polycrystalline silicon layer with the second doping concentration; according to the invention, the optimal charge balance is realized by using the P-type column with gradually increased concentration, so that the breakdown voltage is optimi