Radiation resistant integrated circuit design
First Claim
1. A radiation hardened integrated circuit device on a semiconductor substrate, comprising:
- an outer annular transistor having an outer annular gate electrode disposed on a first diffusion region of said semiconductor substrate, a second diffusion region being bounded by said outer annular gate electrode, a portion of said outer annular gate electrode forming an active channel of said outer annular transistor and being located completely within said first diffusion region; and
at least one inner annular transistor having an inner annular gate electrode disposed on said second diffusion region, said at least one inner annular transistor being surrounded by said outer annular transistor and connected to a field oxide region completely isolated within said outer annular transistor.
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Accused Products
Abstract
Annular transistors are positioned with respect to the n-well diffusion region so that the active channels of the transistors are completely within the diffusion region, thereby avoiding the formation of the edges at the boundary between n+ active channel regions and adjacent field oxide region (the bird'"'"'s beak region), which are susceptible to the effect of the ionizing radiation. The edgeless design of the gate arrays reduces the degradation of the transistors caused by the bird'"'"'s beak leakage, while allowing for an unmodified commercial process flow for fabrication. An outer annular transistor and one or more inner annular transistors may be provided. The outer transistor may be used as an active transistor in the formation of logic circuits, or may provide isolation for the one or more inner transistors, which may be connected to form logic circuits. The design preferably includes a provision for readily disabling the radiation resistant system so the same design can be easily transformed into a non-radiation resistant design. Other electrical components such as a resistor may be formed with another annular gate electrode to isolate the component from the deleterious effects of ionizing radiation, as well.
119 Citations
17 Claims
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1. A radiation hardened integrated circuit device on a semiconductor substrate, comprising:
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an outer annular transistor having an outer annular gate electrode disposed on a first diffusion region of said semiconductor substrate, a second diffusion region being bounded by said outer annular gate electrode, a portion of said outer annular gate electrode forming an active channel of said outer annular transistor and being located completely within said first diffusion region; and
at least one inner annular transistor having an inner annular gate electrode disposed on said second diffusion region, said at least one inner annular transistor being surrounded by said outer annular transistor and connected to a field oxide region completely isolated within said outer annular transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An annular transistor, comprising:
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an outer annular region of a first conductivity type on a semiconductor substrate and surrounded by a field insulator region, said outer annular region including a first contact of an integrated circuit device and having an inner edge surrounding a central area of said substrate;
an inner region of said first conductivity type on said semiconductor substrate, said inner region occupying a portion of said central area including a second contact of said integrated circuit device and separated from said outer annular region by a ring area on said substrate;
a thin insulator layer formed on the surface of said substrate in said ring area; and
a conductive layer formed on said thin insulator layer as a gate electrode of said integrated circuit device. - View Dependent Claims (11, 12)
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13. A semiconductor device, comprising:
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an outer annular region of a first conductivity type on a semiconductor substrate and surrounded by a field insulator region, said outer annular region connected to a reference potential and having an inner edge surrounding a central area of said substrate;
an inner region of said first conductivity type on said semiconductor substrate, said inner region occupying a portion of said central area and separated from said outer annular region by a ring area on said substrate;
a ring insulator layer formed on the surface of said substrate in said ring area;
a conductive layer formed on said ring insulator layer and connected to said reference potential; and
said inner region having first and second electrodes forming a semiconductor component. - View Dependent Claims (14, 15, 16)
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17. A radiation hardened integrated circuit device on a semiconductor substrate, comprising:
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an outer annular region of a first conductivity type on a semiconductor substrate and surrounded by a field insulator region, said outer annular region forming a first electrode of a first integrated circuit device and having an inner edge surrounding a central area of said substrate;
an inner annular region of said first conductivity type on said semiconductor substrate, forming a second electrode of said first integrated circuit device and a first electrode of a second integrated circuit device, said inner annular region occupying a first portion of said central area and separated from said outer annular region by a first ring area on said substrate, said inner annular region having an inner edge surrounding a second portion of said central area of said substrate;
a first thin insulator layer formed on the surface of said substrate in said first ring area;
a first conductive layer formed on said first thin insulator layer as a gate electrode of said first integrated circuit device;
an inner central region of said first conductivity type on said semiconductor substrate, said inner central region occupying part of said second portion of said central area forming a second electrode of said second integrated circuit device and separated from said inner annular region by a second ring area on said substrate;
a second thin insulator layer formed on the surface of said substrate in said second ring area; and
a second conductive layer formed on said second thin insulator layer as a gate electrode of said second integrated circuit device.
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Specification