Taiwan Semiconductor Manufacturing Comp. Ltd.

Chih-Ta Chen

Chia-Shiung Tsai

Yeur-Luen Tu

Cheng-Hsien Chou

Sheng-Chau Chen

Chih-Yu Lai

Shih Pei Chou

Some embodiments of the present disclosure relate to a method in which a functional layer is formed over an upper semiconductor surface of a semiconductor substrate, and a capping layer is formed over the functional layer. A first etchant is used to form a recess through the capping layer and through the functional layer. The recess has a first depth and exposes a portion of the semiconductor substrate there through. A protective layer is formed along a lower surface and inner sidewalls of the recess. A second etchant is used to remove the protective layer from the lower surface of the recess and to extend the recess below the upper semiconductor surface to a second depth to form a deep trench. To prevent etching of the functional layer, the protective layer remains in place along the inner sidewalls of the recess while the second etchant is used.

Deep trench isolation shrinkage method for enhanced device performance

Some embodiments of the present disclosure relate to a deep trench isolation (DTI) structure configured to enhance efficiency and performance of a photovoltaic device. The photovoltaic device comprises a functional layer disposed over an upper surface of a semiconductor substrate, and a pair of pixels formed within the semiconductor substrate, which are separated by the DTI structure. The DTI structure is arranged within a deep trench. Sidewalls of the deep trench are partially covered with a protective sleeve formed along the functional layer prior to etching the deep trench. The protective sleeve prevents etching of the functional layer while etching the deep trench, which prevents contaminants from penetrating the pair of pixels. The protective sleeve also narrows the width of the DTI structure, which increases pixel area and subsequently the efficiency and performance of the photovoltaic device.

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Tainan, Taiwan

Chih-Ta Chen