SOI polysilicon trench refill perimeter oxide anchor scheme

A method for creating a MEMS structure, comprising the steps of:

• providing a silicon substrate having a layer of silicon dioxide disposed thereon and having a layer of silicon disposed on the layer of silicon dioxide;
• creating at least one aperture which extends through the layer of silicon and the layer of silicon dioxide;
• depositing a first material comprising nitride in the at least one aperture, thereby defining an anchor portion;
• depositing a second material over the first material so as to define a cantilevered portion;
• and
• etching the silicon oxide with a chemical etching solution which is selective to the first material.

A method for creating a MEMS structure, comprising the steps of:

• providing a substrate having a sacrificial layer disposed thereon and having a semiconductor layer disposed over the sacrificial layer;
• creating a first trench which extends through the semiconductor silicon layer and the sacrificial layer and which separates the sacrificial layer into a first region enclosed by the first trench and a second region exterior to the first trench;
• depositing a first material into the first trench such that the first material covers the portion of the sacrificial layer exposed by the first trench;
• depositing a second material into the first trench, the second material being distinct from the first material;
• creating a second trench exterior to the first trench which extends through at least the semiconductor layer and exposes at least a portion of the second region of the sacrificial layer;
• and
• contacting the second region of the sacrificial layer, by way of the second trench, with a chemical etching solution adapted to etch the sacrificial layer, said etching solution being selective to the first material.

A method for creating a MEMS structure, comprising the steps of:

• providing a substrate having a sacrificial layer disposed thereon and having a semiconductor layer disposed over the sacrificial layer;
• creating a first trench which extends through the semiconductor silicon layer and the sacrificial layer and which separates the sacrificial layer into a first region enclosed by the first trench and a second region exterior to the first trench;
• depositing a first material into the first trench such that the first material covers the portion of the sacrificial layer exposed by the first trench;
• creating a second trench exterior to the first trench which extends through at least the semiconductor layer and exposes at least a portion of the second region of the sacrificial layer;
• and
• contacting the second region of the sacrificial layer, by way of the second trench, with a chemical etching solution adapted to etch the sacrificial layer, said etching solution being selective to the first material;
• wherein the first material is deposited such that extends beyond the first trench.