A TCAM comprises a plurality of first search lines, a plurality of second search lines, a plurality of memory cell strings and one or more current sensing units. The memory cell strings comprise a plurality of memory cells. The current sensing units are coupled to the memory cell strings. In a search operation, a determination that whether any of the data stored in the memory cell strings matches a data string to be searched is made according to whether the one or more current sensing units detect current from the memory cell strings, or according to the magnitude of the current flowing out from the memory cell strings detected by the one or more current sensing units. Each memory cell includes a first transistor and a second transistor. Gates of the first and second transistors are coupled to a corresponding first search line and a corresponding second search line.

A control circuit controls a column decoder and a row decoder to perform reprogramming where, before the count of reprogramming operations involving erasures, each targeting one of a plurality of memory cells included in a memory cell array, reaches a predetermined number, a first extent (e.g. a sub-block) including the targeted memory cell and being smaller than the entire extent of the memory cell array is used as the unit of reprogramming, and when the count of reprogramming operations reaches the predetermined number, a second extent (e.g. the memory cell array corresponding to one sector) including the targeted memory cell and being larger than the first extent is used as the unit of reprogramming, and resets the count of reprogramming operations each time it reaches the predetermined number.

A semiconductor device includes a gate insulator layer above a semiconductor substrate, a gate electrode above the gate insulating layer, a sidewall insulator layer on sidewalls of the gate electrode and above the substrate, source and drain regions within the substrate on both sides of the gate electrode, a first region within the substrate below a part of the sidewall insulator layer closer to the source region and having an impurity concentration lower than the source region, a second region provided within the substrate below a part of the sidewall insulator layer closer to the drain region and having an impurity concentration lower than the drain region, a channel region provided within the substrate between the first and second regions, and a third region within the substrate below the channel region and including impurities of a different type and having an impurity concentration higher than the channel region.

In an example, a memory array may include a memory cell around at least a portion of a semiconductor. The memory cell may include a gate, a first dielectric stack to store a charge between a first portion of the gate and the semiconductor, and a second dielectric stack to store a charge between a second portion of the gate and the semiconductor, the second dielectric stack separate from the first dielectric stack.

Some embodiments include apparatuses and methods of forming such apparatuses. One of the apparatus includes first memory cells located in different levels in a first portion of the apparatus, second memory cells located in different levels in a second portion of the apparatus, a switch located in a third portion of the apparatus between the first and second portions, first and second control gates to access the first and second memory cells, an additional control gate located between the first and second control gates to control the switch, a first conductive structure having a thickness and extending perpendicular to the levels in the first portion of the apparatus, a first dielectric structure between the first conductive structure and charge-storage portions of the first memory cells, a second dielectric structure having a second thickness between the second conductive structure and a sidewall of the additional control gate, the second thickness being greater than the first thickness.

According to one embodiment, a semiconductor memory device comprises a first memory cell array including a first block and a second block, the first block including a first memory cell, and the second block including a second memory cell; and a controller that performs, in a first period of time in writing, a first program in the first memory cell and the second memory cell.

A content addressable memory cell includes a first floating body transistor and a second floating body transistor. The first floating body transistor and the second floating body transistor are electrically connected in series through a common node. The first floating body transistor and the second floating body transistor store complementary data.

Some embodiments include apparatuses and methods having multiple decks of memory cells and associated control gates. A method includes forming a first deck having alternating conductor materials and dielectric materials and a hole containing materials extending through the conductor materials and the dielectric materials. The methods can also include forming a sacrificial material in an enlarged portion of the hole and forming a second deck of memory cells over the first deck. Additional apparatuses and methods are described.

A TCAM comprises a plurality of first search lines, a plurality of second search lines, a plurality of memory cell strings and one or more current sensing units. The memory cell strings comprise a plurality of memory cells. The current sensing units are coupled to the memory cell strings. In a search operation, a determination that whether any of the data stored in the memory cell strings matches a data string to be searched is made according to whether the one or more current sensing units detect current from the memory cell strings, or according to the magnitude of the current flowing out from the memory cell strings detected by the one or more current sensing units. Each memory cell includes a first transistor, a second transistor and an inverter. The first search line is coupled to the second search line by the inverter.

A content addressable memory cell includes a first floating body transistor and a second floating body transistor. The first floating body transistor and the second floating body transistor are electrically connected in series through a common node. The first floating body transistor and the second floating body transistor store complementary data.