The present invention discloses a multi-bit-per-cell three-dimensional resistive random-access memory (3D-RRAM.sub.MB). It comprises a plurality of RRAM cells stacked above a semiconductor substrate. Each RRAM cell comprises a RRAM layer, which is switched from a high-resistance state to a low-resistance state during programming. By adjusting the programming current, the programmed RRAMs have different resistances.

Certain aspects of the present disclosure are directed to methods and apparatus for programming a device having one or more programmable circuits to implement, for example, a machine learning model. One example apparatus generally includes a plurality of word lines, a plurality of bit lines, and an array of programmable circuits. Each programmable circuit is coupled to a corresponding word line in the plurality of word lines and to a corresponding bit line in the plurality of bit lines and comprises: a main resistor coupled between the corresponding word line and the corresponding bit line, an auxiliary resistor, a fuse coupled in series with the auxiliary resistor, wherein the auxiliary resistor and the fuse are coupled between the corresponding word line and the corresponding bit line, and a programming circuit configured to selectively blow the fuse.

A method for programming an electrically programmable fuse is disclosed. As conductive medium of the electrically programmable fuse exhibits different physical changes under different conditions, the conductive medium is changed from an initial physical state to a first physical state by using a first programming condition to program the electrically programmable fuse from a low resistance state to a medium resistance state, and the conductive medium is changed from the initial physical state or the first physical state to a second physical state by using a second programming condition to program the electrically programmable fuse from the low resistance state or the medium resistance state to a high resistance state. Transitions of three information storage states are achieved through two different programming conditions, so that the information storage density and chip area utilization rate of an electrically programmable fuse device can be significantly improved, and chip size reduction is facilitated.

A bi-sided pattern processor comprises a plurality of storage-processing units (SPU's). Each of the SPU's comprises at least a memory array and a pattern-processing circuit. The preferred pattern processor further comprises a semiconductor substrate with opposing first and second surfaces. The memory array is disposed on the first surface, whereas the pattern-processing circuit is disposed on the second surface. The memory array stores patterns; the pattern-processing circuit processes these patterns; and, they are communicatively coupled by a plurality of inter-surface connections.

A double-biased three-dimensional one-time-programmable read-only memory (3D-OTP) comprises an OTP array stacked on a semiconductor substrate. The OTP array comprises a dummy word line, a plurality of data word lines and data bit lines. The dummy OTP cells at the intersections of the dummy word line and all data bit lines are unprogrammed. During read, both voltages on the dummy word line and a selected data word line are raised.

Various embodiments of the present application are directed towards a one-time-programmable (OTP) implementation using magnetic junctions. In some embodiments, an array comprises multiple magnetic junctions in multiple columns and multiple rows, and the magnetic junctions comprise a first magnetic junction and a second magnetic junction. The first and second magnetic junctions comprise individual top ferromagnetic elements and individual bottom ferromagnetic elements, and further comprise individual barrier elements between the top and bottom ferromagnetic elements. A first barrier element of the first magnetic junction electrically separates first top and bottom ferromagnetic elements of the first magnetic junction. A second barrier element of the second magnetic junction has undergone breakdown, such that it has defects defining a leakage path between second top and bottom ferromagnetic elements of the second magnetic junction. The broken-down state corresponds to a one-time programmed state and is not susceptible to high-temperature change, even at small sizes.

To reduce the pre-programming cost, an efficient three-dimensional one-time-programmable read-only memory (3D-OTP) is disclosed. It comprises a dummy word line and a plurality of dummy bit lines. Only the dummy OTP cells at the intersections of the dummy word line and dummy bit lines are programmed. All other dummy OTP cells are unprogrammed.

A multi-bit-per-cell three-dimensional read-only memory (3D-OTP.sub.MB) comprises a plurality of dummy bit lines. It comprises a plurality of OTP cells stacked above a semiconductor substrate. Each OTP array comprises at least four dummy bit lines.

A circuit includes an operational amplifier including an inverting input terminal capacitively coupled to each of an OTP cell array and an NVM cell array and first and second output terminals, an ADC coupled to the first and second output terminals, thereby configured to receive a differential output voltage from the operational amplifier, and a comparator coupled to the ADC and configured to output a data bit responsive to a digital output signal received from the ADC. The circuit is configured to cause the operational amplifier to generate the differential output voltage based on each of a current received from an OTP cell of the OTP cell array and a voltage received from an NVM cell of the NVM cell array.

The present disclosure provides a multi-state one-time programmable (MSOTP) memory circuit including a memory cell and a programming voltage driving circuit. The memory cell includes a MOS storage transistor, a first MOS access transistor and a second MOS access transistor electrically connected to store two bits of data. When the memory cell is in a writing state, the programming voltage driving circuit outputs a writing control potential to the gate of the MOS storage transistor, and when the memory cell is in a reading state, the programming voltage driving circuit outputs a reading control potential to the gate of the MOS storage transistor.