Method for forming a trench capacitor

A method for manufacturing a deep trench capacitor, comprising:

• defining a silicon substrate a surface;
• forming a layer of silicon nitride over the surface of the silicon substrate;
• depositing a layer of borosilicate glass having a predetermined thickness over the layer of silicon nitride;
• patterning and defining the layer of borosilicate glass to expose two regions of the surface of the silicon substrate separated by a sacrificial mask, wherein the sacrificial mask includes the layer of borosilicate glass and the layer of silicon nitride, the sacrificial mask having a higher etch rate than remaining portions of the patterned and defined layers of silicon nitride and borosilicate glass;
• etching the two regions of the surface of the silicon substrate to form two trenches, wherein the two trenches are separated by a portion of silicon substrate having a height below the surface of the silicon substrate;
• depositing a layer of silicon nitride on the sidewalls of the trenches to form a dielectric layer;
• and
• depositing doped polysilicon into the trenches to form a single capacitor.