Process for digging a deep trench in a semiconductor body and semiconductor body so obtained

摘要

A process for digging deep trenches in a body of semiconductor material envisages: forming a mask (3) having at least one opening (5), above a surface (2a) of a semiconductor body (2); forming a passivating layer (6, 6') conformally on the mask (3) and on the semiconductor body (2) within the opening (5); executing a directional etch so as to first remove the passivating layer (6, 6') at least from on top of the semiconductor body (2) and then etch the semiconductor body (2) through the opening (5). The steps of forming a passivating layer (6, 6') and executing a directional etch are carried out repeatedly in sequence so as to form a trench (10) through the opening (5). In a step of the process, moreover, a tapered portion (10") of the trench (10) is formed, which has a transverse dimension (W") decreasing as a distance (D) from the surface (2a) of the semiconductor body (2) increases.