Patents by Inventor Chandrasekhar R. Gorla
Chandrasekhar R. Gorla 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: 9368207Abstract: Operating ReRAM memory is disclosed herein. The memory cells may be trained prior to initially programming them. The training may help to establish a percolation path. In some aspects, a transistor limits current of the memory cell when training and programming. A higher current limit is used during training, which conditions the memory cell for better programming. The non-memory may be operated in unipolar mode. The memory cells can store multiple bits per memory cell. A memory cell can be SET directly from its present state to one at least two data states away. A memory cell can be RESET directly to the state having the next highest resistance. Program conditions, such as pulse width and/or magnitude, may depend on the state to which the memory cell is being SET. A higher energy can be used for programming higher current states.Type: GrantFiled: January 7, 2015Date of Patent: June 14, 2016Assignee: SanDisk Technologies Inc.Inventors: Abhijit Bandyopadhyay, Roy E Scheuerlein, Chandrasekhar R Gorla, Brian Le
-
Publication number: 20150170742Abstract: Operating ReRAM memory is disclosed herein. The memory cells may be trained prior to initially programming them. The training may help to establish a percolation path. In some aspects, a transistor limits current of the memory cell when training and programming. A higher current limit is used during training, which conditions the memory cell for better programming. The non-memory may be operated in unipolar mode. The memory cells can store multiple bits per memory cell. A memory cell can be SET directly from its present state to one at least two data states away. A memory cell can be RESET directly to the state having the next highest resistance. Program conditions, such as pulse width and/or magnitude, may depend on the state to which the memory cell is being SET. A higher energy can be used for programming higher current states.Type: ApplicationFiled: January 7, 2015Publication date: June 18, 2015Applicant: SANDISK 3D LLCInventors: Abhijit Bandyopadhyay, Roy E. Scheuerlein, Chandrasekhar R. Gorla, Brian Le
-
Patent number: 8995169Abstract: Operating ReRAM memory is disclosed herein. The memory cells may be trained prior to initially programming them. The training may help to establish a percolation path. In some aspects, a transistor limits current of the memory cell when training and programming. A higher current limit is used during training, which conditions the memory cell for better programming. The non-memory may be operated in unipolar mode. The memory cells can store multiple bits per memory cell. A memory cell can be SET directly from its present state to one at least two data states away. A memory cell can be RESET directly to the state having the next highest resistance. Program conditions, such as pulse width and/or magnitude, may depend on the state to which the memory cell is being SET. A higher energy can be used for programming higher current states.Type: GrantFiled: September 12, 2013Date of Patent: March 31, 2015Assignee: SanDisk 3D LLCInventors: Abhijit Bandyopadhyay, Roy E. Scheuerlein, Chandrasekhar R. Gorla, Brian Le
-
Publication number: 20150070966Abstract: Operating ReRAM memory is disclosed herein. The memory cells may be trained prior to initially programming them. The training may help to establish a percolation path. In some aspects, a transistor limits current of the memory cell when training and programming. A higher current limit is used during training, which conditions the memory cell for better programming. The non-memory may be operated in unipolar mode. The memory cells can store multiple bits per memory cell. A memory cell can be SET directly from its present state to one at least two data states away. A memory cell can be RESET directly to the state having the next highest resistance. Program conditions, such as pulse width and/or magnitude, may depend on the state to which the memory cell is being SET. A higher energy can be used for programming higher current states.Type: ApplicationFiled: September 12, 2013Publication date: March 12, 2015Applicant: SanDisk 3D LLCInventors: Abhijit Bandyopadhyay, Roy E. Scheuerlein, Chandrasekhar R. Gorla, Brian Le
-
Publication number: 20150070965Abstract: Non-volatile storage devices having reversible resistance storage elements are disclosed herein. In one aspect, a memory cell unit includes one or more memory cells and a transistor (e.g., FET) that is used to control (e.g., limit) current of the memory cells. The drain of the transistor may be connected to a first end of the memory cell. If the memory cell unit has multiple memory cells then the drain may be connected to a node that is common to a first end of each of the memory cells. The source of the transistor is connected to a common source line. The gate of the transistor may be connected to a word line. The same word line may connect to the transistor gate of several (or many) different memory cell units. A second end of the memory cell is connected to a bit line.Type: ApplicationFiled: September 12, 2013Publication date: March 12, 2015Applicant: SanDisk 3D LLCInventors: Abhijit Bandyopadhyay, Roy E. Scheuerlein, Chandrasekhar R. Gorla, Brian Le
-
Patent number: 8848430Abstract: A method and system for forming, resetting, or setting memory cells is disclosed. One or more programming conditions to apply to a memory cell having a reversible resistivity-switching element may be determined based on its resistance. The determination of one or more programming conditions may also be based on a pre-determined algorithm that may be based on properties of the memory cell. The one or more programming conditions may include a programming voltage and a current limit. For example, the magnitude of the programming voltage may be based on the resistance. As another example, the width of a programming voltage pulse may be based on the resistance. In some embodiments, a current limit used during programming is determined based on the memory cell resistance.Type: GrantFiled: November 18, 2010Date of Patent: September 30, 2014Assignee: SanDisk 3D LLCInventors: Xiying Chen Costa, Roy Scheuerlein, Abhijit Bandyopadhyay, Brian Le, Li Xiao, Tao Du, Chandrasekhar R. Gorla
-
Publication number: 20110205782Abstract: A method and system for forming, resetting, or setting memory cells is disclosed. One or more programming conditions to apply to a memory cell having a reversible resistivity-switching element may be determined based on its resistance. The determination of one or more programming conditions may also be based on a pre-determined algorithm that may be based on properties of the memory cell. The one or more programming conditions may include a programming voltage and a current limit. For example, the magnitude of the programming voltage may be based on the resistance. As another example, the width of a programming voltage pulse may be based on the resistance. In some embodiments, a current limit used during programming is determined based on the memory cell resistance.Type: ApplicationFiled: November 18, 2010Publication date: August 25, 2011Inventors: Xiying Chen Costa, Roy Scheuerlein, Abhijit Bandyopadhyay, Brian Le, Li Xiao, Tao Du, Chandrasekhar R. Gorla
-
Patent number: 6803289Abstract: A method for fabricating a bipolar transistor is provided. In some cases, the method may include patterning an epitaxial layer to expose one or more regions of a semiconductor topography. The method may further include depositing an intermediate layer above the exposed regions and remaining portions of the epitaxial layer. A conductive emitter structure may then be formed above and within the intermediate layer. In another embodiment, the method may include etching a first dielectric layer in alignment with a patterned base of a bipolar transistor while simultaneously etching a second dielectric layer in alignment with a patterned emitter structure of the bipolar transistor. In yet other embodiments, the method may include depositing an intermediate layer which is substantially etch resistant to a resist stripping process. In addition or alternatively, the intermediate layer may include etch characteristics that are substantially similar to a conductive layer formed above the intermediate layer.Type: GrantFiled: June 28, 2002Date of Patent: October 12, 2004Assignee: Cypress Semiconductor Corp.Inventors: Prabhuram Gopalan, K. Nirmal Ratnakumar, Chandrasekhar R. Gorla
-
Patent number: 6366389Abstract: A high contrast ultrahigh speed optically-addressed ultraviolet light modulator exploits the optical anisotropy in a ZnO film epitaxially grown on (01 {overscore (1)}2) sapphire. This device, which could also be realized in a ZnO bulk crystal or similar wide bandgap material, achieves both high contrast and high speed by exploiting the anisotropic bleaching of the anisotropic absorption and concomitant ultrafast polarization rotation near the lowest exciton resonances produced by femtosecond ultraviolet pulses. The resultant modulation in a preferred embodiment is characterized by a contrast ratio of 70:1, corresponding to a dynamic polarization rotation of 12°, and decays to a quasi-equilibrium value within 100 ps.Type: GrantFiled: August 15, 2000Date of Patent: April 2, 2002Inventors: Michael Wraback, Paul H. Shen, Shaohua Liang, Chandrasekhar R. Gorla, Yicheng Lu