Split poly connection via through-poly-contact (TPC) in split-gate based power MOSFETs

摘要

Embodiments of the present disclosure provide a contact structure in a split-gate trench transistor device for electrically connecting the top electrode to the bottom electrode inside the trench. The transistor device comprises a semiconductor substrate and one or more trenches formed in the semiconductor substrate. The trenches are lined with insulating materials along the sidewalls inside the trenches. Each trench has a bottom electrode in lower portions of the trench and a top electrode in its upper portions. The bottom electrode and the top electrode are separated by an insulating material. A contact structure filled with conductive materials is formed in each trench in an area outside of an active region of the device to connect the top electrode and the bottom electrode. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

主权项

1. A method for fabricating a transistor device, the method comprising:
a) forming a plurality of trenches in a semiconductor substrate, each trench in the plurality being lined with an insulating material along sidewalls inside each trench in the plurality; b) forming a bottom electrode in lower portions of each trench in the plurality; c) forming a top electrode in upper portions of each trench in the plurality, wherein the top electrode is separated from the bottom electrode by an inter-electrode insulating layer; and d) forming a plurality of contact structures, each contact structure in the plurality of contact structures being formed in a corresponding trench in the plurality of trenches in an area outside of an active region of the device, wherein each contact structure in the plurality of contact structures penetrates through an opening in a portion of the top electrode in the corresponding trench of the plurality of trenches and through an opening in a corresponding portion of the inter-electrode insulating layer beneath the top electrode in the corresponding trench of the plurality of trenches to reach the bottom electrode in the corresponding trench of the plurality of trenches, and wherein each contact structure in the plurality of contact structures is filled with a conductive material and provides electrical connection between the bottom electrode formed in the corresponding trench in the plurality of trenches and the top electrode formed in the corresponding trench in the plurality of trenches.