Patent application number | Description | Published |
20090154217 | HIGH SPEED OTP SENSING SCHEME - A high speed sensing scheme for a non-volatile memory array is disclosed. The memory array includes non volatile memory cells arranged in a complementary bitline configuration includes precharge circuits for precharging the bitlines to a first voltage level such as VSS, a reference circuits for applying a reference charge on the reference bitlines of the complementary bitline pairs, and bitline sense amplifiers for sensing a voltage differential between the complementary bitline pairs. A voltage on the data bitline being changed when a programmed non-volatile memory cell connected to an activated wordline couples the wordline voltage to the data bitline. | 06-18-2009 |
20100011266 | PROGRAM VERIFY METHOD FOR OTP MEMORIES - A method for executing a program verify operation in a non-volatile memory. A data register having master and slave latching circuits is used for concurrently storing two different words of data. In a program operation, the master latch stores program data which is used for programming selected memory cells. In a program verify operation, the data programmed to the memory cells are read out and stored in the slave latches. In each data register stage, the logic states of both latches are compared to each other, and a status signal corresponding to a program pass condition is generated if opposite logic states are stored in both latches. The master latch in each stage is inverted if programming was successful, in order to prevent re-programming of that bit of data. | 01-14-2010 |
20100202183 | HIGH RELIABILITY OTP MEMORY - A method and system for improving reliability of OTP memories, and in particular anti-fuse memories, by storing one bit of data in at least two OTP memory cells. Therefore each bit of data is read out by accessing the at least two OTP memory cells at the same time in a multi-cell per bit mode. By storing one bit of data in at least two OTP memory cells, defective cells or weakly programmable cells are compensated for since the additional cell or cells provide inherent redundancy. Program reliability is ensured by programming the data one bit at a time, and verifying all programmed bits in a single-ended read mode, prior to normal operation where the data is read out in the multi-cell per bit mode. Programming and verification is achieved at high speed and with minimal power consumption using a novel program/verify algorithm for anti-fuse memory. In addition to improved reliability, read margin and read speed are improved over single cell per bit memories. | 08-12-2010 |
20100220511 | LOW POWER ANTIFUSE SENSING SCHEME WITH IMPROVED RELIABILITY - Generally, a method and circuit for improving the retention and reliability of unprogrammed anti-fuse memory cells. This is achieved by minimizing the tunneling current through the unprogrammed anti-fuse memory cells which can cause eventual gate oxide breakdown. The amount of time a read voltage is applied to the anti-fuse memory cells is reduced by pulsing a read voltage applied to a wordline connected to the unprogrammed anti-fuse memory cells, thereby reducing the tunneling current. Further tunneling current can be reduced by decoupling the unprogrammed anti-fuse memory cells from a sense amplifier that can drive the corresponding bitline to VSS. | 09-02-2010 |
20100244115 | ANTI-FUSE MEMORY CELL - An anti-fuse memory cell having a variable thickness gate oxide. The variable thickness gate oxide has a thick gate oxide portion and a thin gate oxide portion, where the thing gate oxide portion has at least one dimension less than a minimum feature size of a process technology. The thin gate oxide can be rectangular in shape or triangular in shape. The anti-fuse transistor can be used in a two-transistor memory cell having an access transistor with a gate oxide substantially identical in thickness to the thick gate oxide of the variable thickness gate oxide of the anti-fuse transistor. | 09-30-2010 |
20100259965 | HIGH SPEED OTP SENSING SCHEME - A high speed sensing scheme for a non-volatile memory array is disclosed. The memory array includes non volatile memory cells arranged in a complementary bitline configuration includes precharge circuits for precharging the bitlines to a first voltage level such as VSS, a reference circuits for applying a reference charge on the reference bitlines of the complementary bitline pairs, and bitline sense amplifiers for sensing a voltage differential between the complementary bitline pairs. A voltage on the data bitline being changed when a programmed non-volatile memory cell connected to an activated wordline couples the wordline voltage to the data bitline. | 10-14-2010 |
20110019491 | REDUNDANCY SYSTEM FOR NON-VOLATILE MEMORY - A redundancy scheme for Non-Volatile Memories (NVM) is described. This redundancy scheme provides means for using defective cells in non-volatile memories to increase yield. The algorithm is based on inverting the program data for data being programmed to a cell grouping when a defective cell is detected in the cell grouping. Defective cells are biased to either “1” or “0” logic states, which are effectively preset to store its biased logic state. A data bit to be stored in a defective cell having a logic state that is complementary to the biased logic state of the cell results in the program data being inverted and programmed. An inversion status bit is programmed to indicate the inverted status of the programmed data. During read out, the inversion status bit causes the stored data to be re-inverted into its original program data states. | 01-27-2011 |
20110103127 | AND-TYPE ONE TIME PROGRAMMABLE MEMORY CELL - An AND-type anti-fuse memory cell, and a memory array consisting of AND-type anti-fuse memory cells. Chains of AND type anti-fuse cells are connected in series with each other, and with a bitline contact, in order to minimize the area occupied by the memory array. Each AND type anti-fuse cell includes an access transistor serially connectable to the bitline or the access transistors of other AND type anti-fuse cells, and an anti-fuse device. The channel region of the access transistor is connected to the channel region of the anti-fuse device, and both channel regions are covered by the same wordline. The wordline is driven to a programming voltage level for programming the anti-fuse device, or to a read voltage level for reading the anti-fuse device. | 05-05-2011 |
20110312169 | ANTI-FUSE MEMORY CELL - An anti-fuse memory cell having a variable thickness gate dielectric. The variable thickness dielectric has a thick portion and a thin portion, where the thin portion has at least one dimension less than a minimum feature size of a process technology. The thin portion can be rectangular in shape or triangular in shape. The anti-fuse transistor can be used in a two-transistor memory cell having an access transistor with a gate dielectric substantially identical in thickness to the thick portion of the variable thickness gate dielectric of the anti-fuse transistor. | 12-22-2011 |
20110317804 | PROGRAM VERIFY METHOD FOR OTP MEMORIES - A method for executing a program verify operation in a non-volatile memory. A data register having master and slave latching circuits is used for concurrently storing two different words of data. In a program operation, the master latch stores program data which is used for programming selected memory cells. In a program verify operation, the data programmed to the memory cells are read out and stored in the slave latches. In each data register stage, the logic states of both latches are compared to each other, and a status signal corresponding to a program pass condition is generated if opposite logic states are stored in both latches. The master latch in each stage is inverted if programming was successful, in order to prevent re-programming of that bit of data. | 12-29-2011 |
20120182782 | METHODS FOR TESTING UNPROGRAMMED OTP MEMORY - Methods for testing unprogrammed single transistor and two transistor anti-fuse memory cells include testing for connections of the cells to a bitline by comparing a voltage characteristic of a bitline connected to the cell under test to a reference bitline having a predetermined voltage characteristic. Some methods can use test cells having an access transistor identically configured to the access transistor of a normal memory cell, but omitting the anti-fuse device found in the normal memory cell, for testing the presence of a connection of the normal memory cell to the bitline. Such a test cell can be used in a further test for determining the level of capacitive coupling of the wordline voltage to the bitlines relative to that of a normal memory cell under test. | 07-19-2012 |
20120211841 | OTP MEMORY CELL HAVING LOW CURRENT LEAKAGE - A one time programmable memory cell having twin wells to improve dielectric breakdown while minimizing current leakage. The memory cell is manufactured using a standard CMOS process used for core and I/O (input/output) circuitry. A two transistor memory cell having an access transistor and an anti-fuse device, or a single transistor memory cell | 08-23-2012 |
20130128679 | REDUNDANCY SYSTEM FOR NON-VOLATILE MEMORY - A redundancy scheme for Non-Volatile Memories (NVM) is described. This redundancy scheme provides means for using defective cells in non-volatile memories to increase yield. The algorithm is based on inverting the program data for data being programmed to a cell grouping when a defective cell is detected in the cell grouping. Defective cells are biased to either “1” or “0” logic states, which are effectively preset to store its biased logic state. A data bit to be stored in a defective cell having a logic state that is complementary to the biased logic state of the cell results in the program data being inverted and programmed. An inversion status bit is programmed to indicate the inverted status of the programmed data. During read out, the inversion status bit causes the stored data to be re-inverted into its original program data states. | 05-23-2013 |
20140146625 | REDUNDANCY SYSTEM FOR NON-VOLATILE MEMORY - A redundancy scheme for Non-Volatile Memories (NVM) is described. This redundancy scheme provides means for using defective cells in non-volatile memories to increase yield. The algorithm is based on inverting the program data for data being programmed to a cell grouping when a defective cell is detected in the cell grouping. Defective cells are biased to either “1” or “0” logic states, which are effectively preset to store its biased logic state. A data bit to be stored in a defective cell having a logic state that is complementary to the biased logic state of the cell results in the program data being inverted and programmed. An inversion status bit is programmed to indicate the inverted status of the programmed data. During read out, the inversion status bit causes the stored data to be re-inverted into its original program data states. | 05-29-2014 |