Patents by Inventor Mousumi Bhat
Mousumi Bhat 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).
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Patent number: 7112499Abstract: A process is described to form a semiconductor device such as MOSFET or CMOS with shallow junctions in the source/drain extension regions. After forming the shallow trench isolations and the gate stack, sidewall dielectric spacers are removed. A pre-amorphizing implant (PAI) is performed with Ge+ or Si+ ions to form a thin PAI layer on the surface of the silicon regions adjacent to the gate stack. B+ ion implantation is then performed to form source/drain extension (SDE) regions. The B+ implant step is then followed by multiple-pulsed 248 nm KrF excimer laser anneal with pulse duration of 23 ns. This step is to reduce the sheet resistance of the junction through the activation of the boron dopant in the SDE junctions. Laser anneal is then followed by rapid thermal anneal (RTA) to repair the residual damage and also to induce out-diffusion of the boron to yield shallower junctions than the just-implanted junctions prior to RTA.Type: GrantFiled: January 16, 2004Date of Patent: September 26, 2006Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Chyiu Hyia Poon, Leng Seow Tan, Byung Jin Cho, Alex See, Mousumi Bhat
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Publication number: 20060205138Abstract: A method for forming selective P type and N type gates is described. A first gate oxide layer is grown overlying a semiconductor substrate. A polysilicon layer is deposited overlying the first gate oxide layer. The polysilicon layer is patterned to form first NMOS gates. A second gate oxide layer is grown overlying the substrate. A polysilicon-germanium layer is deposited overlying the second gate oxide layer and the first gates. The polysilicon-germanium layer and first gates are planarized to a uniform thickness. The polysilicon first gates and the polysilicon-germanium layer are patterned to form second NMOS polysilicon gates and PMOS polysilicon-germanium gates.Type: ApplicationFiled: March 14, 2005Publication date: September 14, 2006Inventors: Tze Chan, Mousumi Bhat, Jeffrey Chee
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Patent number: 7101746Abstract: A method for forming selective P type and N type gates is described. A gate oxide layer is grown overlying a semiconductor substrate. A polysilicon layer is deposited overlying the gate oxide layer. Germanium ions are implanted into a portion of the polysilicon layer not covered by a mask to form a polysilicon-germanium layer. The polysilicon layer and the polysilicon-germanium layer are patterned to form NMOS polysilicon gates and PMOS polysilicon-germanium gates. In an alternative, nitrogen ions are implanted into the polysilicon-germanium layer and the gates are annealed after patterning to redistribute the germanium ions throughout the polysilicon-germanium layer. In a second alternative, germanium ions are implanted into a first thin polysilicon layer, then a second polysilicon layer is deposited to achieve the total polysilicon layer thickness before patterning the gates.Type: GrantFiled: November 5, 2003Date of Patent: September 5, 2006Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Tze Ho Simon Chan, Mousumi Bhat, Jeffrey Chee
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Publication number: 20050158956Abstract: A process is described to form a semiconductor device such as MOSFET or CMOS with shallow junctions in the source/drain extension regions. After forming the shallow trench isolations and the gate stack, sidewall dielectric spacers are removed. A pre-amorphizing implant (PAI) is performed with Ge+ or Si+ ions to form a thin PAI layer on the surface of the silicon regions adjacent to the gate stack. B+ ion implantation is then performed to form source/drain extension (SDE) regions. The B+ implant step is then followed by multiple-pulsed 248 nm KrF excimer laser anneal with pulse duration of 23 ns. This step is to reduce the sheet resistance of the junction through the activation of the boron dopant in the SDE junctions. Laser anneal is then followed by rapid thermal anneal (RTA) to repair the residual damage and also to induce out-diffusion of the boron to yield shallower junctions than the just-implanted junctions prior to RTA.Type: ApplicationFiled: January 16, 2004Publication date: July 21, 2005Inventors: Chyiu Poon, Leng Tan, Byung Cho, Alex See, Mousumi Bhat
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Patent number: 6897118Abstract: A method for forming a highly activated ultra shallow ion implanted semiconductive elements for use in sub-tenth micron MOSFET technology is described. A key feature of the method is the ability to activate the implanted impurity to a highly active state without permitting the dopant to diffuse further to deepen the junction. A selected single crystalline silicon active region is first amorphized by implanting a heavy ion such as silicon or germanium. A semiconductive impurity for example boron is then implanted and activated by pulsed laser annealing whereby the pulse fluence, frequency, and duration are chosen to maintain the amorphized region just below it's melting temperature. It is found that just below the melting temperature there is sufficient local ion mobility to secure the dopant into active positions within the silicon matrix to achieve a high degree of activation with essentially no change in concentration profile.Type: GrantFiled: February 11, 2004Date of Patent: May 24, 2005Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Chyiu-Hyia Poon, Byung Jin Cho, Yong Feng Lu, Alex See, Mousumi Bhat
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Publication number: 20050095773Abstract: A method for forming selective P type and N type gates is described. A gate oxide layer is grown overlying a semiconductor substrate. A polysilicon layer is deposited overlying the gate oxide layer. Germanium ions are implanted into a portion of the polysilicon layer not covered by a mask to form a polysilicon-germanium layer. The polysilicon layer and the polysilicon-germanium layer are patterned to form NMOS polysilicon gates and PMOS polysilicon-germanium gates. In an alternative, nitrogen ions are implanted into the polysilicon-germanium layer and the gates are annealed after patterning to redistribute the germanium ions throughout the polysilicon-germanium layer. In a second alternative, germanium ions are implanted into a first thin polysilicon layer, then a second polysilicon layer is deposited to achieve the total polysilicon layer thickness before patterning the gates.Type: ApplicationFiled: November 5, 2003Publication date: May 5, 2005Inventors: Tze Ho Chan, Mousumi Bhat, Jeffrey Chee
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Patent number: 6872608Abstract: A method for forming selective P type and N type gates is described. A first gate oxide layer is grown overlying a semiconductor substrate. A polysilicon layer is deposited overlying the first gate oxide layer. The polysilicon layer is patterned to form first NMOS gates. A second gate oxide layer is grown overlying the substrate. A polysilicon-germanium layer is deposited overlying the second gate oxide layer and the first gates. The polysilicon-germanium layer and first gates are planarized to a uniform thickness. The polysilicon first gates and the polysilicon-germanium layer are patterned to form second NMOS polysilicon gates and PMOS polysilicon-germanium gates.Type: GrantFiled: October 30, 2003Date of Patent: March 29, 2005Assignee: Chartered Semiconductor Manufacturing Ltd.Inventors: Tze Ho Chan, Mousumi Bhat, Jeffrey Chee
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Patent number: 6686633Abstract: A semiconductor device includes a memory array of static-random-access memory cells. The SRAM cells are formed using a process flow more closely associated with logic-type devices. The SRAM cells are formed using one semiconductor layer compared to at least three typically seen with SRAM cells. The SRAM cells include many features that allow its dimensions to be scaled to very small dimensions (less than 0.25 microns and possible down to 0.1 microns or even smaller). A unique process integration scheme allows formation of local interconnects (522 and 524), wherein each local interconnect (522, 524) cross couples the inverters of the SRAM and is formed within a single opening (70). Also, interconnect portions (104) of word lines are laterally offset from silicon portions (36) of the same word line, so that the interconnect portions do not interfere with bit line connections.Type: GrantFiled: August 31, 2000Date of Patent: February 3, 2004Assignee: Motorola, Inc.Inventors: Craig S. Lage, Mousumi Bhat, Yeong-Jyh Tom Lii, Andrew G. Nagy, Larry E. Frisa, Stanley M. Filipiak, David L. O'Meara, T. P. Ong, Michael P. Woo, Terry G. Sparks, Carol M. Gelatos
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Patent number: 6291888Abstract: Electrical shorts and leakage paths are virtually eliminated by recessing conductive nodules (52) away from a conductor (72) or not forming the conductive nodules at all. In one embodiment, the refractory metal containing material (52) is recessed from the edge of the opening (32). When forming a nitride layer (54) within the opening (32), conductive nodules (52) are formed from a portion of the refractory metal containing material (20) such that the conductive nodules (52) lie within the recession (42). In another embodiment, an oxide layer (82, 102) is formed adjacent to the refractory metal containing material (20) before forming a nitride layer (84, 112).Type: GrantFiled: December 15, 1999Date of Patent: September 18, 2001Assignee: Motorola Inc.Inventors: Mousumi Bhat, Mark D. Hall, Arkalgud R. Sitaram, Michael P. Woo
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Patent number: 6184073Abstract: A semiconductor device includes a memory array of static-random-access memory cells. The SRAM cells are formed using a process flow more closely associated with logic-type devices. The SRAM cells are formed using one semiconductor layer compared to at least three typically seen with SRAM cells. The SRAM cells include many features that allow its dimensions to be scaled to very small dimensions (less than 0.25 microns and possible down to 0.1 microns or even smaller). A unique process integration scheme allows formation of local interconnects (522 and 524), wherein each local interconnect (522, 524) cross couples the inverters of the SRAM and is formed within a single opening (70). Also, interconnect portions (104) of word lines are laterally offset from silicon portions (36) of the same word line, so that the interconnect portions do not interfere with bit line connections.Type: GrantFiled: December 23, 1997Date of Patent: February 6, 2001Assignee: Motorola, Inc.Inventors: Craig S. Lage, Mousumi Bhat, Yeong-Jyh Tom Lii, Andrew G. Nagy, Larry E. Frisa, Stanley M. Filipiak, David L. O'Meara, T. P. Ong, Michael P. Woo, Terry G. Sparks, Carol M. Gelatos
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Patent number: 6037246Abstract: Electrical shorts and leakage paths are virtually eliminated by recessing conductive nodules (52) away from a conductor (72) or not forming the conductive nodules at all. In one embodiment, the refractory metal containing material (52) is recessed from the edge of the opening (32). When forming a nitride layer (54) within the opening (32), conductive nodules (52) are formed from a portion of the refractory metal containing material (20) such that the conductive modules (52) lie within the recession (42). In another embodiment, an oxide layer (82, 102) is formed adjacent to the refractory metal containing material (20) before forming a nitride layer (84, 112).Type: GrantFiled: September 17, 1996Date of Patent: March 14, 2000Assignee: Motorola Inc.Inventors: Mousumi Bhat, Mark D. Hall, Arkalgud R. Sitaram, Michael P. Woo
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Patent number: 5557569Abstract: A low voltage flash EEPROM X-Cell includes an array of memory cell transistors (24) that constitute asymmetric floating gate memory cells wherein programming is achieved on only one side of the memory cells (24). The programming side of each of the memory cells (24) is connected to one of a plurality of Column Lines (28) at nodes (30). Each node (30) shares the programming side of two of the memory cells (24) and the non-programming side of two of the memory cells (24). The control gates of each of the memory cells (24) are connected to Word Lines (26) associated with rows of the array. To Flash Write all of the memory cells (24), the Column Lines (38) are connected to a negative medium voltage and the row lines (26) are connected to a positive medium voltage.Type: GrantFiled: May 25, 1995Date of Patent: September 17, 1996Assignee: Texas Instruments IncorporatedInventors: Michael C. Smayling, Giulio G. Marotta, Iano D'Arrigo, Giovanni Santin, Georges Falessi, Mousumi Bhat
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Patent number: 5515319Abstract: A non-volatile memory cell 10 is disclosed herein. The cell is formed in a first semiconductor region 12 of a first conductivity type. A second semiconductor region 14 of a second conductivity type formed over the first semiconductor region 12. A third semiconductor region 16 of the first conductivity type formed over the second semiconductor region 14. In the preferred embodiment, the second and third regions 14 and 16 are well regions formed within the first region 12. Other regions such as epitaxially grown layers can also be used. First and second source/drain regions 18 and 20 are formed within the third semiconductor region 16. These second source/drain regions 18 and 20 are separated by a channel region 22. A floating gate 26 overlies at least a portion of the channel region 22 while a control gate 30 overlies the floating gate 26.Type: GrantFiled: October 12, 1993Date of Patent: May 7, 1996Assignee: Texas Instruments IncorporatedInventors: Michael C. Smayling, Iano D'Arrigo, Giovanni Santin, Georges Falessi, Mousumi Bhat
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Patent number: 5349225Abstract: A transistor device 10 formed in a semiconductor layer 12 is disclosed herein. A first source/drain region 14 is formed in the semiconductor layer 12. A second source/drain region 16 is also formed in the semiconductor layer 12 and is spaced from the first source/drain region 14 by a channel region 18. The second source/drain region 16 includes (1) a lightly doped portion 16b adjacent the channel region 18 and abutting the top surface, (2) a main portion 16a abutting the top surface and spaced from the channel region 18 by the lightly doped portion 16b, and (3) a deep portion 16c formed within the layer 12 and spaced from the top surface by the lightly doped portion 16b and the main portion 16a. A gate electrode 20 is formed over at least a portion of the channel region 18 and insulated therefrom.Type: GrantFiled: April 12, 1993Date of Patent: September 20, 1994Assignee: Texas Instruments IncorporatedInventors: Donald J. Redwine, Mousumi Bhat, Michael Smayling