Various implementations described herein are related to a device including a bitcell having a bitcell layout with a first metal layer, a second metal layer and a via programming layer. The device may have a via marking layer provided in the bitcell layout for the bitcell, and the via marking layer controls optical proximity correction of the first metal layer and the second metal layer.

A method to program bitcells of a ROM array uses different programming cells for programming the bitcells with a first or second data item. A first bitcell is programmed by means of a selected programming cell, wherein the programming cell is selected in dependence on operating the memory array as a flipped or a non-flipped memory in multi-bank instance. All other bitcells located in the same column as the first bitcell and subsequent rows are programmed by selected programming cells, wherein the selection of the programming cells is dependent on operating the memory array as a flipped or a non-flipped memory in multi-bank instance and the programming state of the programming cells used for the previously programmed bitcells in the same column.

Disclosed is a ROM memory including a first bitcell including a transistor to store two bits and first and second bit lines to read data stored in the bitcell, a second bitcell including a second transistor connected to the first transistor and sharing the first and second bit lines, and a virtual ground line adjacent the bit lines configured to ground the bitcells.

A small-area high-efficiency read-only memory (ROM) array and a method for operating the same are provided. The small-area high-efficiency ROM array includes bit lines, word common-source lines, and sub-memory arrays. Each sub-memory array includes first, second, third, and fourth memory cells connected to a bit line and a word common-source line. All the memory cells are connected to the same word common-source line and respectively connected to different bit lines. Sharing the gate and the source can not only greatly reduce the overall layout area, but also effectively reduce the load of the memory array to achieve the high-efficiency reading and writing goal.

A method to program bitcells of a ROM array uses different programming cells for programming the bitcells with a first or second data item. A first bitcell is programmed by means of a selected programming cell, wherein the programming cell is selected in dependence on operating the memory array as a flipped or a non-flipped memory in multi-bank instance. All other bitcells located in the same column as the first bitcell and subsequent rows are programmed by selected programming cells, wherein the selection of the programming cells is dependent on operating the memory array as a flipped or a non-flipped memory in multi-bank instance and the programming state of the programming cells used for the previously programmed bitcells in the same column.

The disclosure describes a multi-write read-only memory array and a read-only memory thereof. The read-only memory array includes common-source lines, word bit lines, and sub-memory arrays. The common-source lines include a first common-source line and a second common-source line. The word bit lines include a first word bit line and a second word bit line. Each sub-memory array includes four memory cells. Each memory cell is coupled to the word bit line and the common-source line. The read-only memory includes a field-effect transistor and a capacitor. The source of the field-effect transistor is coupled to the word bit line. The drain of the field-effect transistor is coupled to the common-source line. The capacitor is coupled to the gate of the field-effect transistor and the word bit line.

A drain programmed read-only memory includes a plurality of bit lines for each drain-programmed transistor. In addition, the drain-programmed read-only memory includes a pair of ground lines for each drain-programmed transistor. A decoder decodes a plurality of bits from each drain-programmed transistor by determining which bit line (if any) and which ground line is coupled to the drain-programmed transistor.

A drain programmed read-only memory includes a plurality of bit lines for each drain-programmed transistor. In addition, the drain-programmed read-only memory includes a pair of ground lines for each drain-programmed transistor. A decoder decodes a plurality of bits from each drain-programmed transistor by determining which bit line (if any) and which ground line is coupled to the drain-programmed transistor.

Various implementations described herein are related to a device including a bitcell having a bitcell layout with a first metal layer, a second metal layer and a via programming layer. The device may have a via marking layer provided in the bitcell layout for the bitcell, and the via marking layer controls optical proximity correction of the first metal layer and the second metal layer.