Silicon-on-insulator (SOI) read only memory (ROM) array and method of making a SOI ROM
First Claim
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1. A method of fabricating a Read Only Memory (ROM) on a silicon-on-insulator (SOI) wafer, said method comprising the steps of:
- a) forming a plurality of stripes oriented in a first direction in a silicon surface layer;
b) undercutting ones of said plurality of stripes, cavities being formed along at least one edge of said ones;
c) filling said cavities with a conductive material;
d) forming a plurality of diffusions in an upper surface of said ones, said diffusions forming diodes in said upper surface;
e) forming a plurality of conductive contacts, each of said plurality of conductive contacts contacting one of said diodes at said upper surface; and
f) forming a plurality of conductive lines in a second direction orthogonal to said first direction, a ROM cell being located at each intersection of one of said plurality of conductive lines with one of said plurality of silicon stripes.
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Abstract
A silicon-on-insulator (SOI) Read Only Memory (ROM), and a method of making the SOI ROM. ROM cells are located at the intersections of stripes in the surface SOI layer with orthogonally oriented wires on a conductor layer. Contacts from the wires connect to ROM cell diodes in the upper surface of the stripes. ROM cell personalization is the presence or absence of a diode and/or contact.
34 Citations
22 Claims
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1. A method of fabricating a Read Only Memory (ROM) on a silicon-on-insulator (SOI) wafer, said method comprising the steps of:
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a) forming a plurality of stripes oriented in a first direction in a silicon surface layer; b) undercutting ones of said plurality of stripes, cavities being formed along at least one edge of said ones; c) filling said cavities with a conductive material; d) forming a plurality of diffusions in an upper surface of said ones, said diffusions forming diodes in said upper surface; e) forming a plurality of conductive contacts, each of said plurality of conductive contacts contacting one of said diodes at said upper surface; and f) forming a plurality of conductive lines in a second direction orthogonal to said first direction, a ROM cell being located at each intersection of one of said plurality of conductive lines with one of said plurality of silicon stripes. - View Dependent Claims (2, 3, 4, 5)
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6. A method of fabricating an Integrated Circuit (IC) including a Read Only Memory (ROM), said method comprising the steps of:
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a) forming a plurality of stripes oriented in a first direction in a semiconductor layer; b) forming straps along the underside of each stripe; c) forming at least one diode in an upper surface at least one stripe; d) selectively forming conductive contacts to upper surfaces of said plurality of stripes; and e) forming a plurality of conductive lines in a second direction orthogonal to said first direction, a ROM cell being located at each intersection of one of said plurality of conductive lines with one of said plurality of stripes. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of fabricating a silicon-on-insulator (SOI) Integrated Circuit (IC) including a Read Only Memory (ROM), said method comprising the steps of:
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a) forming a plurality of trenches through a silicon surface layer oriented in a first direction, said plurality of trenches defining silicon stripes; b) undercutting ones of said silicon stripes, cavities being formed along at least one edge of said ones; c) filling said cavities with a conductive material; d) selectively forming diodes in an upper surface of said silicon stripes; e) selectively forming a conductive contact to each of said diodes; and f) forming a plurality of metal lines in a second direction orthogonal to said first direction, a ROM cell being located at each intersection of one of said plurality of metal lines with one of said plurality of silicon stripes, ROM cell contents being determined by connection of a metal line to an underlying diode. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification