Wafer with recessed plug

摘要

In one embodiment, a method of forming a plug includes providing a base layer, providing an intermediate oxide layer above an upper surface of the base layer, providing an upper layer above an upper surface of the intermediate oxide layer, etching a trench including a first trench portion extending through the upper layer, a second trench portion extending through the oxide layer, and a third trench portion extending into the base layer, depositing a first material portion within the third trench portion, depositing a second material portion within the second trench portion, and depositing a third material portion within the first trench portion.

主权项

1. A wafer comprising:
a base layer; an intermediate oxide layer above an upper surface of the base layer; a first upper layer above an upper surface of the intermediate oxide layer; a trench including a first trench portion extending through the first upper layer, a second trench portion extending through the intermediate oxide layer, and a third trench portion extending only partially into the base layer; a plug, the plug including
a first material portion deposited within the third trench portion;a second material portion deposited within the second trench portion; anda third material portion deposited within the first trench portion; and a gap in the intermediate oxide layer, the gap exposing at least a portion of the second material portion.