摘要:
A DRAM is described including a plurality of operable storage cells, each cell including a capacitance for storing a charge indicative of data. The charge tends to dissipate below an acceptable level after a predetermined time interval T1 for a majority of the operable cells and for a minority of the operable cells, it dissipates below the acceptable level after a shorter time interval T2. The time between DRAM refresh cycles is adjusted so as to be greater than time interval T2. The DRAM comprises: a plurality of redundant storage cells; a decoder for receiving the address of an operable memory cell and providing a first output if the address indicates one of the operable cells of the minority of cells and a second output if the address indicates one of the operable cells of the majority. A switching circuit is responsive to the first output to enable access of a redundant stoarge cell and to prevent access of the minority storage cell. In a preferred embodiment, the redundant storage cells are configured as static storage circuits.
摘要:
An improved latch-up protection circuit is disclosed which prevents damage to a CMOS integrated circuit chip due to transient surges or internal-circuitry initiated latch-ups and which clears any latch-up condition or SCR mode. In each embodiment, the latch-up protection circuit is integrated with an on-chip voltage regulation circuit which provides on-chip power to the internal chip circuitry. A first approach to implementing the latch-up protection circuit is to detect an average current through the power transistor of the voltage regulation circuit over a few microseconds. Should the average current exceed a preset value, then the power transistor is turned off and the power (V.sub.DDI) supplied to the internal chip circuitry is reduced to zero, thereby removing the latch-up condition. In a second approach, the on-chip voltage (V.sub.DDI) supplied to internal chip circuitry is compared with a reference voltage signal representative of the occurrence of a latch-up condition, i.e., with the nominal external power supply. When the on-chip power supply voltage V.sub.DDI becomes lower than the trigger voltage, then the power transistor and voltage regulation circuit is disabled, thereby reducing the latch-up condition. Both CMOS and NMOS implementations of the combination voltage regulation and latch-up protection circuit are disclosed.
摘要:
A voltage regulator is provided for controlling an on-chip voltage generator which produces a boost voltage across a charge reservoir for supply to one input of a plurality of word line drivers in a memory array. The regulator is configured such that the charge reservoir voltage will track the power supply voltage and the difference between the power supply voltage and the charge reservoir voltage will be maintained substantially constant over a predefined power supply range. The voltage regulator includes a bandgap reference generator, a first differential circuit for producing a transition voltage from the reference voltage and the power supply voltage, a first transistor for comparing the power supply voltage with the boost voltage, a second transistor for comparing the transition voltage with the reference voltage and a latching comparator for equating the signal outputs from the first and second transistors so as to define a control signal for the on-chip voltage generator. Along with further specific details of the voltage regulator, a preferred bandgap reference generator is described.
摘要:
Disclosed is a Dynamic Random Access Memory (DRAM) cell which includes a storage capacitor disposed in a trench formed in a semiconductor substrate and an access transistor disposed in a well which is opposite in conductivity type to that of the substrate and a buried oxide collar which surrounds an upper portion of the trench.
摘要:
A folded bitline DRAM cell is described which includes a trench capacitor and a planar-configured access transistor. The access transistor is stacked over the capacitor and has a first terminal connected thereto. The access transistor includes a planar-oriented gate. A first wordline has a minor surface in contact with the gate and a major surface that is oriented orthogonally to the gate. An insulating pedestal is positioned adjacent the gate and a passing wordline is positioned on the pedestal, the passing wordline having a major surface parallel to the first wordline. In another embodiment, the folded bitline DRAM cell includes a vertically oriented access transistor having one terminal formed on the upper extent of a contact to the trench capacitor, to provide optimum electrical connection thereto.
摘要:
A stacked bit-line architecture utilizing high density cross-point memory arrays forms a DRAM semiconductor memory device. The true and complementary bit-line pairs connected to the respective memory cell arrays are formed in two metal layers, one above the other. A bit-line interconnector region is provided that uses a third interconnection layer together with the first and second layers to transpose the vertical stacking of each pair and to transpose the planar alignment of adjacent bit-line pairs. The DRAM memory cell array has a high density cross-point memory cell architecture that behaves electrically as a folded bit-line array.
摘要:
A new interdigitated folded bit line (IFBL) architecture for a future generation high density semiconductor memory design is disclosed. In the architecture, the basic cross-point memory cells are organized orthogonally in rows and columns to form an array matrix. The bit lines run in a row direction while the word lines run in a column direction. Transfer transistors are designed to be shared with the same drain junction and the same bit line contact in order to save area. A choice of at least two described embodiments are provided. In one embodiment, referred to as the offset bit line structure, the bit lines are constructed by using two layers of interconnection lines to connect the interdigitated cells associated to it. By connecting the bit line contacts and with two different interconnecting layers and in an alternating row order, the true and complement bit lines and will run parallel to both sides of the memory array. In another embodiment, referred to as the side wall bit line structure, the bit lines are constructed by using the conductive side wall spacer rails to connect the interdigitated cells associated to it. By connecting the side wall bit line contacts with two sided-side wall spacer rails in an alternating row order, the true and complement bit lines will run parallel to both sides of the memory array.
摘要:
A high density substrate plate DRAM cell memory device and process are described in which a buried well region is formed adjacent to deep trench capacitors such that the substrate region of DRAM transfer FETs can be electrically isolated from other FETs on a semiconductor substrate. The buried region is partially formed by ion implantation and diffusion to intersect the walls of the deep trenches.
摘要:
Sequentially terminated write enable pulses applied to respective input ports of a multi-port memory cell is effective to establish a priority among those input ports and provide unconditionally unambiguous writing to a memory cell when write operations are concurrently attempted at two or more ports of that cell, as may be encountered during rigorous testing procedures. Memory structure, particularly that of the input port circuits, is simplified and operational speed is enhanced since signal propagation through a comparator or logic circuit is avoided. Time required for testing of large memory arrays is also significantly reduced.
摘要:
A new interdigitated folded bit line (IFBL) architecture for a future generation high density semiconductor memory design is disclosed. In the architecture, the basic cross-point memory cells are organized orthogonally in rows and columns to form an array matrix. The bit lines run in a row direction while the word lines run in a column direction. Transfer transistors are designed to be shared with the same drain junction and the same bit line contact in order to save area. A choice of at least two described embodiments are provided. In one embodiment, referred to as the offset bit line structure, the bit lines are constructed by using two layers of interconnection lines to connect the interdigitated cells associated to it. By connecting the bit line contacts and with two different interconnecting layers and in an alternating row order, the true and complement bit lines and will run parallel to both sides of the memory array. In another embodiment, referred to as the side wall bit line structure, the bit lines are constructed by using the conductive wall spacer rails to connect the interdigitated cells associated to it. By connecting the side wall bit line contacts with two sided-side wall spacer rails in an alternating row order, the true and complement bit lines will run parallel to both sides of the memory array.