Patents by Inventor Howard L. Tigelaar

Howard L. Tigelaar has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5410162
    Abstract: An apparatus and method for rapidly changing the temperature of a semiconductor wafer, in order to perform electrical tests or stress at elevated temperature, and then cool rapidly to ambient temperature. The apparatus is comprised of a wafer support 17, capable of supporting the wafer, mounted on top of a rapid thermal processing (RTP) illuminator 20 (lamps, preferably halogen), and including one or more probe needles 22, capable of contacting the wafer to perform electrical measurements. A semiconductor wafer 16 is placed upon the wafer support 17 and the RTP illuminator 20 located beneath is activated, rapidly elevating the wafer to the desired temperature. Electrical tests may be performed as desired during the process.
    Type: Grant
    Filed: October 15, 1993
    Date of Patent: April 25, 1995
    Assignee: Texas Instruments Incorporated
    Inventors: Howard L. Tigelaar, Mehrdad M. Moslehi
  • Patent number: 5300456
    Abstract: A method of forming a metal-to-metal antifuse. An antifuse stack 32 is formed comprising a first metal layer 16, an antifuse dielectric layer, and an etchstop layer. The etchstop layer may, for example, comprise an oxide layer 24 and an amorphous silicon layer 28. An antifuse via 44 is etched through an interlevel dielectric layer 36 to the antifuse stack 32. Next, a portion of the etchstop layer at the bottom of via 44 is removed. Finally, a second layer of metal 48 is deposited to fill antifuse via 44 and etched to form the desired interconnections.
    Type: Grant
    Filed: June 17, 1993
    Date of Patent: April 5, 1994
    Assignee: Texas Instruments Incorporated
    Inventors: Howard L. Tigelaar, George Misium
  • Patent number: 5273926
    Abstract: An electrically-erasable and programmable read-only memory cell includes a gate insulator layer formed on the face of a semiconductor layer having a first conductivity type. A conductive floating gate is formed on the gate insulator layer and has first and second portions with a gap substantially laterally separating the first and second portions. An interlevel insulator layer is formed on exposed faces of the floating gate. A conductive control gate is formed on the interlevel insulator layer in the gap and to be capacitively coupled to the floating gate. A source region and a drain region of a second conductivity type are formed beside opposite exterior lateral margins of the floating gate. The EEPROM cell of the invention avoids channel length alignment problems found in prior art EEPROM cells.
    Type: Grant
    Filed: March 12, 1992
    Date of Patent: December 28, 1993
    Assignee: Texas Instruments Incorporated
    Inventor: Howard L. Tigelaar
  • Patent number: 5262846
    Abstract: A contact-free floating-gate non-volatile memory cell array and process with silicided NSAG bitlines and with source/drain regions buried beneath relatively thick silicon oxide. The bitlines have a relatively small resistance, eliminating the need for parallel metallic conductors with numerous bitline contacts. The array has relatively small bitline capacitance and may be constructed having relatively small dimensions. Isolation between bitlines is by thick field oxide. Wordlines may be formed from silicided polycrystalline or other material with low resistivity. Coupling of programming and erasing voltages to the floating gate is improved by extending the gates over the thick field oxide and perhaps by using an insulator with relatively high dielectric constant between the control gate and the floating gate. The sides of the floating gates are defined with a single patterning step. The resulting structure is a dense cross-point array of programmable memory cells.
    Type: Grant
    Filed: August 20, 1991
    Date of Patent: November 16, 1993
    Assignee: Texas Instruments Incorporated
    Inventors: Manzur Gill, Howard L. Tigelaar
  • Patent number: 5216270
    Abstract: A non-volatile memory cell 10 can be fabricated by doping a semiconductor substrate 8 to form source 12 and drain 14 such that at least one small undoped region remains in source 12. A first insulation layer 26a is formed over the source 12 such that the thickness of the layer is less over the undoped region than the doped region while insulation regions 26b and 20 are simultaneously formed over the drain 14 and channel 16 regions. The insulation layer 26a formed above the undoped region of the source 12 is etched to form a tunnel window 28 and then a thin insulation layer is formed over the tunnel window 28. A conductive floating gate 16 is formed over a portion of the first insulation layer 26a which includes the tunnel window 28, over the channel region 16 and over a portion of the second insulation region 26b. Next, an insulation region 24 is formed over the floating gate 16 and a control gate 18 is formed over the insulation region 24. Other structures and methods are also disclosed.
    Type: Grant
    Filed: February 28, 1991
    Date of Patent: June 1, 1993
    Assignee: Texas Instruments Incorporated
    Inventors: Cetin Kaya, Howard L. Tigelaar, Mauzur Gill
  • Patent number: 5200350
    Abstract: A contact-free floating-gate non-volatile memory cell array and process with silicided NSAG bitlines and with source/drain regions buried beneath relatively thick silicon oxide. The bitlines have a relatively small resistance, eliminating the need for parallel metallic conductors with numerous bitline contacts. The array has relatively small bitline capacitance and may be constructed having relatively small dimensions. Isolation between wordlines and between bitlines is by thick field oxide regions. A thick field oxide strip separates each ground conductor/bitline pair. Wordlines may be formed from silicided polycrystalline or other material with low resistivity. Coupling of programming and erasing voltages to the floating gate is improved by extending the gates over the thick field oxide and perhaps by using an insulator with relatively high dielectric constant between the control gate and the floating gate. The resulting structure is a dense cross-point array of programmable memory cells.
    Type: Grant
    Filed: July 26, 1991
    Date of Patent: April 6, 1993
    Assignee: Texas Instruments Incorporated
    Inventors: Manzur Gill, Howard L. Tigelaar
  • Patent number: 5159570
    Abstract: An EEPROM memory cell having sidewall floating gates (28, 28a, 28b) is disclosed. Sidewall floating gates (28, 28a, 28b) are formed on sidewalls (30, 32) of a central block (22). Spaced apart bit lines (36, 36a, 36b) are formed to serve as memory cell sources and drains. Sidewall floating gates (28a, 28b) are capable of being programmed independently of one another. When control gate (18) is actuated and either bit line (36a) or bit line (36b) is used to read the device, four separate memory states may be identified depending on whether either, neither or both of the sidewall floating gates (28a, 28b) have been programmed.
    Type: Grant
    Filed: May 7, 1991
    Date of Patent: October 27, 1992
    Assignee: Texas Instruments Incorporated
    Inventors: Allan T. Mitchell, Howard L. Tigelaar
  • Patent number: 5130267
    Abstract: A metal-to-polysilicon capacitor, a floating-gate transistor containing such a capacitor, and a method for making the same is disclosed. The bottom plate of the capacitor is formed over a field oxide structure, and the capacitor dielectric is deposited thereover. A first metal layer, such as titanium nitride or a titanium-tungsten alloy, is formed over the capacitor dielectric, and is patterned and etched to define the top plate of the capacitor and, accordingly, the capacitor size. Multilevel dielectric is formed thereover, and a contact via to the top plate is etched therethrough. Metallization is sputtered overall, to make contact to the top plate and elsewhere in the circuit.
    Type: Grant
    Filed: October 28, 1991
    Date of Patent: July 14, 1992
    Assignee: Texas Instruments Incorporated
    Inventors: Cetin Kaya, Howard L. Tigelaar
  • Patent number: 5120571
    Abstract: A contact-free floating-gate non-volatile memory cell array and process with silicided NSAG bitlines and with source/drain regions buried beneath relatively thick silicon oxide. The bitlines have a relatively small resistance, eliminating the need for parallel metallic conductors with numerous bitline contacts. The array has relatively small bitline capacitance and may be constructed having relatively small dimensions. Isolation between wordlines and between bitlines is by thick field oxide regions. A thick field oxide strip separates each ground conductor/bitline pair. Wordlines may be formed from silicided polycrystalline or other material with low resistivity. Coupling of programming and erasing voltages to the floating gate is improved by extending the gates over the thick field oxide and perhaps by using an insulator with relatively high dielectric constant between the control gate and the floating gate. The four sides of the floating gates are defined with a single patterning step.
    Type: Grant
    Filed: January 7, 1991
    Date of Patent: June 9, 1992
    Assignee: Texas Instruments Incorporated
    Inventors: Manzur Gill, Howard L. Tigelaar
  • Patent number: 5108941
    Abstract: A metal-to-polysilicon capacitor, a floating-gate transistor containing such a capacitor, and a method for making the same is disclosed. The bottom plate of the capacitor is formed over a field oxide structure, and the multilevel dielectric is deposited thereover. The multilevel dielectric is removed from the capacitor area, and an oxide/nitride dielectric is deposited over the exposed bottom plate and over the multilevel by way of LPCVD. A first layer of titanium/tungsten is preferably deposited prior to contact etch, and the contacts to moat and unrelated polysilicon are formed. Metallization is sputtered overall, and the metal and titanium/tungsten are cleared to leave the metallization filling the contact holes, and a capacitor having a titanium/tungsten and metal top plate.
    Type: Grant
    Filed: March 19, 1990
    Date of Patent: April 28, 1992
    Assignee: Texas Instrument Incorporated
    Inventors: James L. Paterson, Howard L. Tigelaar
  • Patent number: 5106773
    Abstract: Circuitry 12 is formed at the face of a layer semiconductor 34. The circuitry includes a plurality of contact points 22 and 24. At least one anti-fuse 14 is formed in a layer vertically displaced from circuitry 12. Anti-fuse 14 is operable to selectively connect together certain ones of said contact points 22 and 24.
    Type: Grant
    Filed: October 9, 1990
    Date of Patent: April 21, 1992
    Assignee: Texas Instruments Incorporated
    Inventors: Cheing-Long Chen, David K. Liu, Howard L. Tigelaar
  • Patent number: 5095345
    Abstract: A contact-free floating-gate non-volatile memory cell array and process with silicided NSAG bitlines and with source/drain regions buried beneath relatively thick silicon oxide. The bitlines have a relatively small resistance, eliminating the need for parallel metallic conductors with numerous bitline contacts. The array has relatively small bitline capacitance and may be constructed having relatively small dimensions. Isolation between wordlines and between bitlines is by thick field oxide regions. A thick field oxide strip separates each ground conductor/bitline pair. Wordlines may be formed from silicided polycrystalline or other material with low resistivity. Coupling of programming and erasing voltages to the floating gate is improved by extending the gates over the thick field oxide and perhaps by using an insulator with relatively high dielectric constant between the control gate and the floating gate. The resulting structure is a dense cross-point array of programmable memory cells.
    Type: Grant
    Filed: August 30, 1990
    Date of Patent: March 10, 1992
    Assignee: Texas Instruments Incorporated
    Inventors: Manzur Gill, Howard L. Tigelaar
  • Patent number: 5084418
    Abstract: Bitlines (34) are formed by creating a diffused region (26) around the sidewalls and bottom of a trench (20). The trench (20) is filled with a conductive region (30), typically a refractory metal, refractory metal silicide.
    Type: Grant
    Filed: January 16, 1990
    Date of Patent: January 28, 1992
    Assignee: Texas Instruments Incorporated
    Inventors: Agerico L. Esquivel, Howard L. Tigelaar, Allan T. Mitchell
  • Patent number: 5079670
    Abstract: A metal-to-polysilicon capacitor, a floating-gate transistor containing such a capacitor, and a method for making the same is disclosed. The bottom plate of the capacitor is formed over a field oxide structure, and the multilevel dielectic is deposited thereover. The multilevel dielectric is removed from the capacitor area, and an oxide/nitride dielectric is deposited over the exposed bottom plate and over the multilevel by way of LPCVD. A first layer of titanium/tungsten is preferably deposited prior to contact etch, and the contacts to moat and unrelated polysilicon are formed. Metallization is sputtered overall, and the metal and titanium/tungsten are cleared to leave the metallization filling the contact holes, and a capacitor having a titanium/tungsten and metal top plate.
    Type: Grant
    Filed: February 27, 1990
    Date of Patent: January 7, 1992
    Assignee: Texas Instruments Incorporated
    Inventors: Howard L. Tigelaar, James L. Paterson
  • Patent number: 5065220
    Abstract: A metal-to-polysilicon capacitor, a floating-gate transistor containing such a capacitor, and a method for making the same is disclosed. The bottom plate of the capacitor is formed over a field oxide structure, and the multilevel dielectric is deposited thereover. The multilevel dielectric is removed from the capacitor area, and an oxide/nitride dielectric is deposited over the exposed bottom plate and over the multilevel by way of LPCVD. A first layer of titanium/tungsten is preferably deposited prior to contact etch, and the contacts to moat and unrelated polysilicon are formed. Metallization is sputtered overall, and the metal and titanium/tungsten are cleared to leave the metallization filling the contact holes, and a capacitor having a titanium/tungsten and metal top plate.
    Type: Grant
    Filed: May 3, 1988
    Date of Patent: November 12, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: James L. Paterson, Howard L. Tigelaar
  • Patent number: 5057886
    Abstract: A non-volatile memory is provided which provides a floating gate (42) disposed over control gate (38) in order to increase the coupling therebetween. The degree of coupling may be varied by adjusting the area of the floating gate formed over the control gate relative to the area of the floating gate over the substrate.
    Type: Grant
    Filed: December 21, 1988
    Date of Patent: October 15, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: Bert R. Riemenschneider, Howard L. Tigelaar
  • Patent number: 5053839
    Abstract: One embodiment of the invention provides an EPROM and a method of fabricating an EPROM with enhanced capacitive coupling. Trenched memory cells each comprise a pleat-shaped floating gate with the control gate nested in a fold of the floating gate to increase the coupling ratio with the control gate. As a result higher programming speed and improved cell density may be obtained for a given programming voltage. Formation of bit lines along trench walls results in lower bit line resistivity for a given cell density.
    Type: Grant
    Filed: August 21, 1990
    Date of Patent: October 1, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: Agerico L. Esquivel, Allan T. Mitchell, Howard L. Tigelaar
  • Patent number: 5045490
    Abstract: One embodiment of the invention provides an EPROM and a method of fabricating an EPROM with enhanced capacitive coupling. Trenched memory cells each comprise a pleat-shaped floating gate with the control gate nested in a fold of the floating gate to increase the coupling ratio with the control gate. As a result higher programming speed and improved cell density may be obtained for a given programming voltage. Formation of bit lines along trench walls results in lower bit lines resistivity for a given cell density.
    Type: Grant
    Filed: August 21, 1990
    Date of Patent: September 3, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: Agerico L. Esquivel, Allan T. Mitchell, Howard L. Tigelaar
  • Patent number: 5036020
    Abstract: A microelectronic device (10a) provides an improved capacitor (12a) having two plate members (22a, 26a) capacitively coupled via a dielectric layer (24). In accordance with the invention, contact portions (32a, 42a) have substantially twice the thickness of functional portions (28, 38) prior to etching oxide (16) to form contacts (18, 20). In this fashion, the total thickness of capacitor (12a) is minimized yet the thickness of contact portions (32a, 42a) is maximized. Hence, maximum thickness for etching purposes [to construct metal contact 18, 20)] is achieved. Thus the topographical profile of microelectronic device (10a) is essentially reduced to half that of the prior art while the necessary pre-etch thickness of contact portions (32a) and (42a) is maintained. Other pre-etch thickness proporations may be utilized between conductive layer subportions (34) and (36) and conductive layer subportions (44) and (46).
    Type: Grant
    Filed: August 31, 1990
    Date of Patent: July 30, 1991
    Assignee: Texas Instrument Incorporated
    Inventor: Howard L. Tigelaar
  • Patent number: 5023680
    Abstract: A contact-free floating-gate non-volatile memory cell array and process with silicided NSAG bitlines and with source/drain regions buried beneath relatively thick silicon oxide. The bitlines have a relatively small resistance, eliminating the need for parallel metallic conductors with numerous bitline contacts. The array has relatively small bitline capacitance and may be constructed having relatively small dimensions. Isolation between wordlines and between bitlines is by thick field oxide regions. A thick field oxide strip separates each ground conductor/bitline pair. Wordlines may be formed from silicided polycrystalline or other material with low resistivity. Coupling of programming and erasing voltages to the floating gate is improved by extending the gates over the thick field oxide and perhaps by using an insulator with relatively high dielectric constant between the control gate and the floating gate. The four sides of the floating gates are defined with a single patterning step.
    Type: Grant
    Filed: November 10, 1988
    Date of Patent: June 11, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: Manzur Gill, Howard L. Tigelaar