Method for forming capacitor of mixed-mode device
AssigneeUnited Microelectronics Corp.
InventorYen-Lin Ding
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Abstract
A method of forming a capacitor of a mixed-mode device is described. Trenches used for forming a trench-type capacitor are simultaneously formed in a provided substrate while forming a shallow trench isolation. A conductive region used as a lower electrode is formed by ion implantation. A gate oxide layer, used for dielectric film, and a polysilicon layer, used as a gate and an upper electrode, are formed over the substrate and over the trenches. A trench-type capacitor is thus formed.
Claims8
A method for forming a capacitor of a mixed-mode device, comprising the steps of:
- providing a substrate;
- forming a first trench in a first area and a plurality of second trenches different from the first area in the substrate, wherein the first trench is used for isolation and the second trenches are used to form a capacitor;
- forming a liner oxide layer on the substrate exposed within the first trench and the second trenches;
- forming a dielectric layer to fill the first trench and the second trenches;
- forming a mask layer over the substrate and the first trench, wherein the second trenches are exposed by the mask layer;
- removing the liner oxide layer and the dielectric layer exposed by the mask layer;
- performing a first ion implantation to form a first conductive region in the substrate around the second trenches;
- removing the mask layer;
- forming a gate oxide layer over the substrate;
- forming a conductive layer over and filling the second trenches;
- and
- performing a second ion implantation to form a second conductive region in the substrate around the conductive layer, wherein the second conductive region electrically connects to the first conductive region and an external power source.
A method for forming a capacitor of a mixed-mode device, comprising the steps of:
- providing a substrate having a first trench in a first area and a plurality of second trenches different from the first area therein, wherein the plurality of second trenches are used to form a trench-type capacitor;
- forming a liner oxide layer and a dielectric layer to fill the first trench and to form a shallow trench isolation structure;
- forming a first conductive region in the substrate around the second trenches;
- forming a gate oxide layer on the exposed substrate within the second trenches;
- forming a conductive layer over the second trenches, whereby the trench-type capacitor is formed;
- and
- forming a second conductive region in the substrate beside the first conductive region.
Dependencies are inferred from the claim text.