Manufacture of high breakdown voltage semiconductor element

Abstract

Abstract PURPOSE:To enable a pn junction surface to be formed taking a bevel shape to realize high breakdown voltage by a method wherein etching speed is specified respectively in the two processes using high speed type and low speed type silicon etchants. CONSTITUTION:In the first surface processing process, the scratched layer on a bevel surface caused during the sand blasting process is removed using a high speed type HF-HNO3-CH3COOH silicon etchant at the etching rate of 20-100mum/min. Next, in the second process, the bevel surface is smoothed using a low speed type HF-HNO3-CH3COOH silicon etchant at the etching rate of 0-10mum/min. Consequently, a pn junction surface can be processed taking bevel shape in less crystalline defect facilitating the spread of depletion layer on the pn junction surface. Through these procedures, the surface can be provided with high breakdown voltage in the bevel structure.

Inventors

• 👤 Koji Yoshida
• 👤 Masanori Inuta

Bibliographic Details