| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming a semiconductor trench structure whose breakdown voltage is improved. SOLUTION: A process, in which the inside of a trench 2 is etched by varying the etching rate for Si, is provided. This process is provided with a process, wherein Si is etched at a first etching rate so as to remove residue products in the trench 2, and a process, wherein the Si is etched at a second etch rate higher than the first etch rate so as to form a scooped part 10 which extends from the peripheral part of the trench toward the interface between an SiO2 film 8 and an Si substrate 1. Leakage current is decreased with this cleaning, and further concentration of electric field at the peripheral part is suppressed by forming the scooped part 10, and in addition, pressure resistance thereof is improved.
|
