Method for reducing resistance of contact window
First Claim
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1. A method of forming an electrically enhanced contact surface in a self-aligned contact window comprising the steps of:
- providing a substrate having a plurality of gates, wherein each gate has a spacer on each side wall of the gate and a cap layer on the gate;
forming an oxide layer over the gates and the substrate;
forming a photo-resist layer with an opening on the oxide layer, wherein the opening exposes a part of the oxide layer aligned with a predetermined source/drain region of the substrate between the gates;
etching the oxide layer using the photo-resist layer, the spacer and the cap layer as a mask to form the contact window to expose the predetermined source/drain region;
etching the predetermined source/drain region by a soft-etching process and forming a recess with a rough surface within the contact window; and
performing an ion implantation to form a charge barrier underlying a top surface of the predetermined source/drain region to prevent charge leakage due to the rough surface of the recess.
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Abstract
A method of reducing resistance of a contact. A semiconductor substrate having at least a conductive lines formed thereon is provided. A self-aligned contact window is formed to expose a part of the substrate. A recess with a ragged surface is formed on the exposed part of substrate within the contact window.
6 Citations
20 Claims
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1. A method of forming an electrically enhanced contact surface in a self-aligned contact window comprising the steps of:
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providing a substrate having a plurality of gates, wherein each gate has a spacer on each side wall of the gate and a cap layer on the gate; forming an oxide layer over the gates and the substrate; forming a photo-resist layer with an opening on the oxide layer, wherein the opening exposes a part of the oxide layer aligned with a predetermined source/drain region of the substrate between the gates; etching the oxide layer using the photo-resist layer, the spacer and the cap layer as a mask to form the contact window to expose the predetermined source/drain region; etching the predetermined source/drain region by a soft-etching process and forming a recess with a rough surface within the contact window; and performing an ion implantation to form a charge barrier underlying a top surface of the predetermined source/drain region to prevent charge leakage due to the rough surface of the recess. - View Dependent Claims (2, 3, 4, 5, 6, 7, 18, 20)
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8. A method of forming an electrically enhanced contact surface in a self-aligned contact window comprising the steps of:
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providing a substrate on which at least a pair of gates is formed with a spacer on each side wall of the gate, a cap layer on the gate and an oxide layer over the gate and the substrate; patterning the oxide layer to form a contact window to expose the substrate between the gates; etching the substrate by a soft-etching process and forming a recess with a rough surface within the contact window; and performing an ion implantation to form a charge barrier underlying the rough surface of the recess to prevent charge leakage due to the rough surface. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 19)
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Specification