Electronic device including a tapered trench and a conductive structure therein and a process of forming the same

An electronic device comprising:

• a semiconductor layer overlying a substrate and having a primary surface that generally corresponds to a first plane;
• and
• a trench having a first portion, a second portion, and a third portion, wherein:
• the first, second, and third portions are disposed within the semiconductor layer;
• the first and third portions are tapered;
• and
• from a cross-sectional view, the second portion is defined by a sidewall that lies along a second plane that intersects the first plane at an angle of greater than approximately 70°.

An electronic device comprising:

• a semiconductor layer overlying a substrate and having a primary surface, wherein the primary surface generally lies substantially along a plane;
• a trench having a tapered shape;
• a conductive structure within a relatively narrower portion of the trench;
• and
• a conductive electrode within a relatively wider portion of the trench, wherein the conductive electrode and the conductive structure are electrically insulated from each other.

A process of forming an electronic device comprising:

• providing a semiconductor layer overlying a substrate and having a primary surface;
• patterning the semiconductor layer to define a trench having a tapered portion;
• forming a first insulating layer within the tapered portion;
• forming a sacrificial plug within the tapered portion;
• removing a first portion of the first insulating layer from the tapered portion, wherein the sacrificial plug substantially protects a second portion of the first insulating layer when removing the first portion of the first insulating layer;
• removing the sacrificial plug;
• and
• forming a conductive electrode at a location from which the sacrificial plug was removed.