Patent ID: 9224803
Filing Date: 2015-12-29
Classification: H01L

Abstract:
1. A semiconductor film stack having a contact structure, comprising: a first plurality of layers having a top surface and a contact layer; a second plurality of layers having a bottom surface, the second plurality of layers being disposed above the first plurality of layers; a shaped stop layer disposed between the first plurality of layers and the second plurality of layers, wherein the shaped stop layer has formed therein a trench having tapered sidewalls, the tapered sidewalls extending through the entire shaped stop layer from the bottom surface of the second plurality of layers to the top surface of the first plurality of layers, the trench having an upper width and a lower width, the lower width being smaller than the upper width; a relatively large contact hole extending through the second plurality of layers; and a relatively small contact hole extending downward from a lower extent of the trench to an upper extent of the contact layer, the small contact hole having a cross-section substantially the same as the lower width of the trench.