Dual dielectric structure for suppressing lateral leakage current in high fill factor arrays
View Patent ↗A structure and method for suppressing lateral leakage current in full fill factor image arrays includes dual dielectric passivation layer. A first passivation layer includes a material that is an insulator, has a low dielectric constant to minimize capacitive coupling between the contacts, and is low stress to prevent cracking. A second passivation layer includes a thin oxide or nitride layer over the first passivation layer.
1. A method for making a high fill factor image array comprising the steps:
providing a plurality of source-drain metal contacts on a substrate;
depositing a first passivation layer over the plurality of source-drain metal contacts and the substrate;
reducing the lateral leakage current between the plurality of source-drain metal contacts in the high fill factor image array by depositing a second passivation layer over the first passivation layer, the second passivation layer being thinner than the first passivation layer;
opening a plurality of via holes through the first and second passivation layers to the plurality of source-drain metal contacts;
depositing a layer of conductive material over the plurality of source-drain metal contacts and the second passivation layer;
depositing a first doped a-Si layer as an optically active layer over the layer of conductive material;
patterning the first doped a-Si layer and the layer of conductive material to form collection electrodes;
depositing a continuous layer of i a-Si disposed on the second passivation layer and the first doped a-Si layer;
depositing a continuous second layer of doped a-Si over the continuous layer of i a-Si;
depositing an upper conductive layer over the second layer of doped a-Si; and
patterning to form the image array.
2. The method for making a high fill factor image array according to claim 1 , wherein the first passivation layer comprises silicon oxynitride, BCB, or a polyamide.
3. The method for making a high fill factor image array according to claim 1 , wherein the second passivation layer is an oxide.
4. The method for making a high fill factor image array according to claim 1 , wherein the second passivation layer has a thickness of about 1000 Å.
5. A high fill factor image array formed by:
providing a plurality of source-drain metal contacts on a substrate;
depositing a first passivation layer over the plurality of source-drain metal contacts and the substrate;
reducing the lateral leakage current between the plurality of source-drain metal contacts in the high fill factor image array by depositing a second passivation layer over the first passivation layer, the second passivation layer being thinner than the first passivation layer;
opening a plurality of via holes through the first and second passivation layers over the plurality of source-drain metal contacts;
depositing a layer of conductive material on the plurality of source-drain metal contacts and over the second passivation layer;
depositing a first doped a-Si layer as an optically active layer over the layer of conductive material;
patterning the first doped a-Si layer and the layer of conductive material to form collection electrodes;
depositing a continuous layer of i a-Si disposed on the second passivation layer and over the first doped a-Si layer;
depositing a continuous second layer of doped a-Si over the continuous layer of i a-Si;
depositing an upper conductive layer over the continuous second layer of doped a-Si; and
patterning to form the image array.
6. The high fill factor image array of claim 5 , wherein the first passivation layer comprises at least one of silicon oxynitride, BCB, or a polyimide.
7. The high fill factor image array of claim 5 , wherein the second passivation layer is an oxide.
8. The high fill factor image array of claim 5 , wherein the second passivation layer has a thickness of about 1000 Å.
9. A method for making a high fill factor image array comprising:
providing a plurality of source-drain metal contacts;
depositing a first passivation layer over the plurality of source-drain metal contacts;
reducing the lateral leakage current between the plurality of source metal contacts in the high fill factor image array by depositing a second passivation layer over the first passivation layer being thinner than the first passivation layer;
opening a plurality of via holes through the first and second passivation layers to expose the plurality of source-drain metal contacts;
depositing a layer of conductive material on the plurality of source-drain metal contacts, such that the layer of conductive material makes electrical contact with the plurality of source-drain metal contacts;
depositing a first doped a-Si layer as an optically active layer of conductive material;
patterning the a-Si layer and the layer of conductive material to form collection electrodes;
depositing sensor material comprising a continuous layer of i a-Si over the collection electrodes and at least a portion of the second passivation layer;
depositing a continuous layer of doped a-Si over the continuous layer of i a-Si; depositing a conductive layer over the continuous layer of doped a-Si; and
patterning conductive layer to form an upper electrode.
10. The method for making a high fill factor image array according to claim 9 , wherein the first passivation layer comprises silicon oxynitride, BCB, or a polyamide.
11. The method for making a high fill factor image array according to claim 9 , wherein the second passivation layer is an oxide.
12. The method for making a high fill factor image array according to claim 9 , wherein the second passivation layer has a thickness of about 1000 Å.