TWI584281B - Method for healing phase-change memory device and applications thereof - Google Patents

Description

Repair method of phase change memory component and its application

The present invention relates to a method of repairing a phase change memory element, and more particularly to a method of repairing a phase change memory element comprising a chalcogenide and other materials.

Phase change based memory materials, such as chalcogenides or other similar materials, can cause a phase change between an amorphous phase and a crystalline phase by application of a suitable current. The amorphous phase has a higher resistivity than the crystalline phase, which can be easily sensed and used as an indicator. Further, these characteristics are used to produce a non-volatile memory that can be read or written by random access, that is, a phase change memory.

The phase change memory data is stored by the conversion of the active region of the phase change material between the amorphous phase and the crystalline phase. For example, a phase change material in the memory cell can be heated above a transition temperature by applying a low voltage current pulse to cause the phase change memory material in the active region to transition from the amorphous phase to the crystalline phase, thereby The change in the resistance state of the material from the initial resistance state 100 or the high resistance state 102 to the change in the low resistance state 101 is hereinafter referred to as a set. another In addition, by applying a transient high current density pulse to melt or destroy the crystal structure of the phase change memory material, at least part of the phase change material can be maintained in the structure of the amorphous phase, thereby making the resistance state of the thermal phase change material self. The change from the low resistance state 101 to the high resistance state 102 is hereinafter referred to as reset.

Referring to FIG. 1, FIG. 1 is a diagram showing a distribution (bit count) of memory cells having different resistance states in a phase change memory according to a conventional technique. Each of the memory cells can have at least one high resistance state 102 or a low resistance state 101 by setting or resetting. Each of the resistance states corresponds to a range of resistances that do not overlap each other. The difference between the highest resistance R1 of the low resistance state 101 and the lowest resistance R2 of the high resistance state 102 may define a read interval for distinguishing whether the memory cell is in the low resistance state 101 or the high resistance state 102. The data stored in the memory cell can be determined by the resistance of the memory cell being higher or lower than the critical resistance value 103 in the read interval, and the memory cell is determined to be "0" corresponding to the low resistance state 101. The state either corresponds to the "1" state of the high resistance state 102.

However, after undergoing multiple resets and/or setup operations, the phase change memory material may be generated due to reset and/or set operation times, positional differences in the memory cell array, process conditions, or exposed ambient temperature factors. An aging phenomenon that causes an offset in the electronic properties of the phase change memory material (including resistance states, current-resistance relationships, or other electronic properties). For example, the memory cells in the high resistance state 102 may re-crystallize the phase change memory material in the active region due to the electrical energy or thermal stress applied by the reset and/or set operation, resulting in a gradual decrease in resistance, leading to the operating current. taller and taller. Even because the lowest resistance R2 of the high resistance state 102 is less than the critical resistance value 103 causes a bit error problem.

Therefore, there is a need to provide a more advanced method of repairing phase change memory components to improve the aging of memory materials experienced by conventional techniques.

An embodiment of the present specification is to provide a method for repairing a phase change memory element, the repair method comprising the steps of: firstly providing at least one memory cell, the memory cell comprising shift current-resistance characteristics The phase change memory material of the function. Next, a healing stress is applied to the phase change memory material to convert the offset current-resistance characteristic function of the phase change memory material into an initial current-resistance characteristic function. Wherein, the offset current-resistance characteristic function is substantially a translation of function of the current-resistance characteristic function.

Another embodiment of the present specification is directed to a method of operating a phase change memory device, the method comprising the steps of: first providing a phase change memory component having a plurality of memory cells, wherein each memory cell has Phase change memory material. Next, the phase change memory material of the at least one memory cell has an offset current-resistance characteristic function, and the memory cell having the function of the offset current-resistance characteristic is set to the first state. Then, applying a restoring stress to at least one memory cell having the first state, and converting the offset current-resistance characteristic function of the memory cell into an initial current-resistance characteristic function; wherein the offset current-resistance characteristic function is substantially current - The translation function of the resistance characteristic function. A memory cell having an initial current-resistance characteristic function is set to the second state. In the first state and the second state, in these memories Read the data in the cell.

According to the above embodiment, the present invention provides a method for repairing a phase change memory element by applying a restoring stress to a phase change memory material of a memory cell (because of the number of reset and/or set operations, in the array) The structure, material variation, process conditions, or exposed ambient temperature factors. The electronic properties of the aged phase change memory material, such as the current-resistance characteristic function of the phase change memory material, are restored from the offset state to the beginning. Initial state. In order to solve the problem of the increase of the operating current caused by the aging of the memory material due to the phase change of the memory cell, the problem of the memory cell is even generated.

In addition, the recoverability between the offset current-resistance characteristic function of the phase change memory material and the initial current-resistance characteristic function is utilized to provide a way for the memory cell to access another data. Therefore, the storage density of the data is greatly increased without changing the structure of the phase change memory element.

100‧‧‧ initial resistance state

101‧‧‧Low resistance state

102‧‧‧High resistance state

103‧‧‧critical resistance value

200‧‧‧ memory cells

201‧‧‧ bottom electrode

202‧‧‧ dielectric layer

203‧‧‧ memory layer

203a‧‧‧active area

204‧‧‧ top electrode

301‧‧‧Initial current-resistance characteristic function

302‧‧‧Offset current-resistance characteristic function

303‧‧‧Arrow

1010‧‧‧ phase change memory components

1012‧‧‧ memory array

1014‧‧‧ character line decoder

1016‧‧‧ character line

1018‧‧‧ bit line decoder

1020‧‧‧ bit line

1022‧‧‧ busbar

1024‧‧‧Induction circuit and data input structure

1026‧‧‧ data bus

1028‧‧‧ data input line

1030‧‧‧Other circuits

1032‧‧‧ data output line

1034‧‧‧ Controller

1036‧‧‧bias circuit

S51‧‧‧ provides a phase change memory element that contains at least one memory cell with a phase change memory material and a phase change memory material with an offset current-resistance characteristic function

S52‧‧‧Bake process of phase change memory materials

S53‧‧‧Check the step to confirm whether the offset current-resistance characteristic function is converted to the initial current-resistance characteristic function

S54‧‧‧Determine whether to perform another rewrite step on the repaired memory cell

S55‧‧‧ applies another stress current to the phase change memory material of the memory cell, and converts the initial current-resistance characteristic function of the phase change memory material into the offset current-resistance characteristic function.

S61‧‧‧ provides a phase change memory component that contains at least one memory cell with phase change memory material, and this phase change memory material has an offset current-resistance characteristic function

S62‧‧‧ Apply a return current to the phase change memory material

S63‧‧‧Check the step to confirm whether the offset current-resistance characteristic function is converted to the initial current-resistance characteristic function

S64‧‧‧Determine whether to perform another rewrite step on the repaired memory cell

S65‧‧‧ applies a stress current to the phase change memory material of the memory cell 200, and converts the initial current-resistance characteristic function of the phase change memory material into an offset current-resistance characteristic function.

71‧‧‧ Providing phase change memory components with a plurality of memory cells

72‧‧‧Make at least one phase change memory material of memory cells with offset current-resistance Characteristic function

73‧‧‧Set the memory cell with the offset current-resistance characteristic function as the first state

74‧‧‧ Applying a restoring stress to at least one memory cell having the first state, thereby converting the offset current-resistance characteristic function of the memory cell into an initial current-resistance characteristic function

705‧‧‧Set the memory cell with the initial current-resistance characteristic function to the second state

706‧‧‧ Reading data in memory cells by first state and second state

R1‧‧‧highest resistance in low resistance state

R2‧‧‧lowest resistance in high resistance state

The above-described embodiments and other objects, features and advantages of the present invention will become more apparent and understood. A diagram showing the number distribution of memory cells having two resistance states in a phase change memory; and FIG. 2 is a schematic cross-sectional view showing the structure of a memory cell in a memory matrix of a phase change memory device according to an embodiment of the present invention; The figure shows a phase change material in a memory cell according to an embodiment of the invention. A current-resistance relationship diagram; FIG. 4 is a simplified circuit block diagram of a phase change memory component according to an embodiment of the invention; and FIG. 5 is a diagram showing a repair phase change memory according to an embodiment of the invention. A flow chart of a method for changing a phase change memory material in a memory cell of a body element; and a sixth flow chart showing a method for repairing a phase change memory material in a memory cell of a phase change memory element according to another embodiment of the present invention; Figure 7 is a diagram showing the operation of a phase change memory device in accordance with an embodiment of the present invention.

The invention provides a method for repairing a phase change memory component and an application thereof, which can solve the problem of aging of a phase change memory material. The above-described embodiments and other objects, features and advantages of the present invention will become more apparent and understood.

However, it must be noted that these specific embodiments and methods are not intended to limit the invention. The invention may be practiced with other features, elements, methods and parameters. The preferred embodiments are merely illustrative of the technical features of the present invention and are not intended to limit the scope of the invention. Equivalent modifications and variations will be made without departing from the spirit and scope of the invention. In the different embodiments and the drawings, the same elements will be denoted by the same reference numerals.

Referring to FIG. 2, FIG. 2 is a cross-sectional view showing the structure of a memory cell 200 of a phase change memory device according to an embodiment of the invention. In some embodiments of the invention, a phase change memory component can include a plurality of (eg, millions) of memory cells 200. The memory cell 200 includes a bottom electrode 201, a dielectric layer 202, a memory layer 203, and a top electrode 204. The bottom electrode 201 extends through the dielectric layer 202; the memory layer 203 includes a phase change material; and the top electrode 204 is located above the memory layer 203. In the present embodiment, the bottom electrode 201 is coupled to a terminal of an access device (not shown), and the top electrode 204 can be coupled to a bit line or can be a part of a bit line.

The material constituting the bottom electrode 201 and the top electrode 204 may include, for example, titanium nitride (TiN) or tantalum nitride (TaN). Alternatively, it may also comprise tungsten (W), tungsten nitride (WN), titanium aluminum nitride (AlTiN), or aluminum tantalum nitride (AlTaN), or one or more elemental dopants, one or more The elemental dopant is selected from the group consisting of bismuth (Si), carbon (C), germanium (Ge), chromium (Cr), titanium (Ti), tungsten, molybdenum (Mo), aluminum (Al), tantalum (Ta). A group of copper (Cu), platinum (Pt), iridium (Ir), lanthanum (La), nickel (Ni), nitrogen (N), oxygen (O), ruthenium (Ru), and combinations thereof.

The basic phase change material constituting the memory layer 203 includes germanium (Ge ₂ Sb ₂ Te ₅ ). In some embodiments of the invention, an additive may be doped in the substantially phase change material, such as ruthenium dioxide, while an additive concentration profile is formed along the interelectrode current path between the bottom electrode 201 and the top electrode 204. The concentration profile), in turn, defines an active region 203a comprised of doped phase change material.

In some embodiments of the invention, the phase change material of active region 203a has an initial electronic characteristic. For example, when a set of detected pulse currents is applied to the phase change material in the active region 203a, a current-resistance relationship flowing through the active region 203a can be detected. Referring to FIG. 3, FIG. 3 is a diagram showing a current-resistance relationship of a phase change material in a memory cell according to an embodiment of the invention. The current-resistance of the doped phase change material may constitute a functional pattern, hereinafter referred to as the initial current-resistance characteristic function 301.

Referring to FIG. 4, FIG. 4 is a simplified circuit block diagram of a phase change memory component 1010 including a plurality of memory cells 200 in accordance with an embodiment of the present invention. In some embodiments of the invention, the phase change memory component 1010 includes a memory array 1012, a word line decoder 1014, a plurality of word line lines 1016, a bit line (row) decoder 1018, and a plurality of bit lines. 1020, bus bar 1022, and sensing circuit and data input structure 1024. Wherein, word line 1016 is arranged along rows in memory array 1012, and word line decoder 1014 is coupled to memory array 1012 via word line 1016. The bit lines 1020 are arranged along the columns in the memory array 1012, and the bit line (row) decoder 1018 is electrically connected to the memory array 1012 via the bit lines 1020 for reading, setting, and resetting. Phase change memory cells (not shown) in this array 1012. The address is supplied to the word line decoder 1014 and the bit line decoder 1018 via the bus 1022. The sensing circuit and data input structure 1024 are coupled to the bit line decoder 1018 via the data bus 1026. The information provided from the input/output port of the phase change memory element 1010, or from other circuits 1030 internal or external to the phase change memory element 1010, via Data input line 1028 is input to the sensing circuit and data input structure 1024. The data output from the sensing circuit and data input structure 1024 is provided to other data destinations external to the phase change memory component 1010 via the data output line 1032. Controller 1034 can be applied to the bias configuration of the phase change memory array by using a state machine to control the applied voltage and current supplied from the voltage and current sources in bias circuit 1036. In addition, other circuits 1030, such as general purpose processor application circuitry, special purpose application circuitry, or a combination of the two, may also be included in phase change memory component 1010.

The memory cell 200 of the phase change memory component undergoes multiple resets and/or setup operations, the phase change memory material may be read, reset, and/or set by the number of times or current density, or because of phase change memory. The environmental factors (such as temperature or thermal stress) exposed by the material cause aging of electronic properties. In some embodiments of the invention, the aging phenomenon of the electronic characteristics includes a phenomenon in which the initial current-resistance characteristic function 301 is shifted. In the present embodiment, the translational phenomenon of the initial current-resistance characteristic function 301 can be measured by applying a set of detection pulses to the phase change material in the active region 203a of the memory cell 200.

For example, referring again to FIG. 3, when the phase change memory material of the memory cell 200 exhibits an aging phenomenon of electronic characteristics, the initial current-resistance characteristic function 301 of the phase change material is converted into an offset current-resistance characteristic function 302. The offset current-resistance characteristic function 302 is substantially a translation function of the initial current-resistance characteristic function 301. In other words, the initial current-resistance characteristic function 301 and the offset current-electricity The function graph of the resistance characteristic function 302 is substantially unchanged, the only difference is that the coordinates of the function pattern are relatively changed, and the function pattern of the offset current-resistance characteristic function 302 is laterally displaced (as indicated by arrow 303).

In order to improve the aging phenomenon of the phase change memory material in the memory cell 200, some embodiments of the present invention provide a method of repairing the phase change memory element described below. Referring to FIG. 5, FIG. 5 is a flow chart showing a method for repairing a phase change memory element according to an embodiment of the invention. The method for repairing a phase change memory component includes the steps of first providing a phase change memory component to be incorporated into a memory cell 200 having a phase change memory material having an offset current-resistance The characteristic function 302 (as shown in step S51).

As previously described, the step of providing a memory cell 200 having a phase change memory material that offsets the current-resistance characteristic function 302 includes performing a set operation, a reset operation, or any combination of the above, one A stress current is applied to the phase change memory material of the memory cell 200 to convert the initial current-resistance characteristic function 301 of the phase change memory material into an offset current-resistance characteristic function 302. Additionally, other electrical, thermal, or mechanical stresses applied to the phase change memory material by the operating environment, or any combination thereof, may also cause the initial current-resistance characteristic function 301 of the phase change memory material to be converted to an offset current-resistance characteristic function 302. .

Next, a return stress is applied to the phase change memory material to convert the offset current-resistance characteristic function 302 of the phase change memory material into an initial current-resistance characteristic function 301. In some embodiments of the invention, the step of applying a restoring stress to the phase change memory material comprises: performing a baking process on the phase change memory material The offset current-resistance characteristic function 302 of the phase change memory material is converted to an initial current-resistance characteristic function 301 (as depicted in step S52). In this embodiment, the baking temperature of the baking process is substantially between 300 ° C and 400 ° C; and the baking time is substantially between 1 minute and 30 minutes.

Then, a detecting step is performed to confirm whether the offset current-resistance characteristic function 302 is converted to the initial current-resistance characteristic function 301 (as shown in step S53). If the offset current-resistance characteristic function 302 is not converted to the initial current-resistance characteristic function 301, then return to step S52 to perform another baking process on the phase change memory material, or simultaneously increase the baking temperature or baking time. If the offset current-resistance characteristic function 302 has been converted to the initial current-resistance characteristic function 301, it may be decided whether to perform another rewriting step on the repaired memory cell 200 (as shown in step S54). . To perform the rewriting step of the initial current-resistance characteristic function, another stress current can be applied to the phase change memory material of the memory cell 200, so that the initial current of the phase change memory material depicted in FIG. 3 - The resistance characteristic function 302 is then converted to an offset current-resistance characteristic function 302 (as depicted in step S55). If the rewriting step of the initial current-resistance characteristic function is not performed, the repair operation of the phase change memory material is completed.

Please refer to FIG. 6. FIG. 6 is a flow chart showing a method for repairing a phase change memory element according to another embodiment of the present invention. The method of repairing a phase change memory component includes the steps of first providing a phase change memory component having at least one memory cell 200 comprising a memory material, and the phase change memory material has an offset current-resistance characteristic function 302. (as shown in step S61).

In some embodiments of the invention, the step of providing a memory cell 200 having a phase change memory material that offsets the current-resistance characteristic function 302 includes performing a set operation, a reset operation, or any combination of the above operations on the memory cell 200. A stress current is applied to the phase change memory material of the memory cell 200 to convert the initial current-resistance characteristic function 301 of the phase change memory material into an offset current-resistance characteristic function 302. Wherein, the stress current has an upper limit value and a lower limit value. In a preferred embodiment of the invention, the magnitude of the stress current is substantially between 200 microamperes (μA) and 500 microamperes.

Next, a restoring stress is applied to the phase change memory material to convert the offset current-resistance characteristic function of the phase change memory material into an initial current-resistance characteristic function. In some embodiments of the invention, the step of applying a restoring stress to the phase change memory material includes applying a return current to the phase change memory material to cause the offset current-resistance characteristic function 302 of the phase change memory material to be converted to an initial current a resistance characteristic function 301 (as depicted in step S62). In some embodiments of the invention, the magnitude of the recovery current is substantially between 1 microamperes and 100 microamperes. In this embodiment, the recovery current is preferably substantially between one-half of the upper limit of the stress current and one-fifth of the lower limit of the stress current (ie, substantially between 250 microamperes and 40 degrees). Between micro amps).

Then, a detecting step is performed to confirm whether the offset current-resistance characteristic function is converted into an initial current-resistance characteristic function (as shown in step S63). If the offset current-resistance characteristic function 302 is not converted to the initial current-resistance characteristic function 301, returning to step S62 and applying another return current to the phase change memory material, Or at the same time increase the current density of the recovery current. If the offset current-resistance characteristic function 302 has been converted to the initial current-resistance characteristic function 301, it may be decided whether to perform another re-writing step on the repaired memory cell 200 (as shown in step S64). To perform the rewriting step of the initial current-resistance characteristic function, a stress current can be applied to the phase change memory material of the memory cell 200, so that the initial current of the phase change memory material depicted in FIG. 3 is The resistance characteristic function 302 is then converted to an offset current-resistance characteristic function 302 (as depicted in step S65). If the rewriting step of the initial current-resistance characteristic function is not performed, the repair operation of the phase change memory material is completed.

Since the phase-change memory device current-resistance characteristic function of the memory cell 200 has a recoverable characteristic that can be converted from the initial state to the off-state and then from the initial state to the off-state. Therefore, another method of accessing the memory cell 200 different from that shown in FIG. 1 (writing, rewriting, and reading of data by the high resistance state 102 or the low resistance state 100) can be provided.

Please refer to FIG. 7. FIG. 7 is a diagram showing a method of operating a phase change memory device according to an embodiment of the invention. The operation of the phase change memory component 1010 includes the steps of first providing a phase change memory component having a plurality of memory cells 200 (as depicted in step 71), wherein each memory cell has a phase change memory material. Next, the phase change memory material of the at least one memory cell 200 is provided with an offset current-resistance characteristic function 302 (as shown in step 702), and the memory cell having the offset current-resistance characteristic function 301 is set to the first state ( As shown in step 703). Then, applying a restoring stress to at least one memory cell having the first state, causing the offset current-resistance characteristic function 302 of the memory cell 200 to be converted into an initial power The current-resistance characteristic function 301 (as depicted in step 74); wherein the offset current-resistance characteristic function 302 is substantially a translational function of the current-resistance characteristic function 302. The memory cell 200 having the initial current-resistance characteristic function 301 is set to the second state (as shown in step 75). Data is also read in these memory cells 200 by the first state and the second state (as shown in step 76). Since the setting and conversion of the current-resistance characteristic function of the memory cell 200 has been described in detail in the foregoing embodiments, it will not be described herein.

In this embodiment, the memory cell 200 having the offset current-resistance characteristic function 302 can be set to the first state, which is affected by electrical energy, thermal stress, mechanical stress, or any combination thereof, and will be uncharged, The memory cell 200 having an initial current-resistance characteristic function after being subjected to thermal stress, mechanical stress, or any combination thereof, or subjected to the aforementioned phase change memory material repairing method, is set to the second state. The phase change memory element 1010 illustrated in FIG. 4 can perform data reading on the memory cells 200 in the memory array 1012 by the first state and the second state.

It is also noted that, in still other embodiments of the present invention, the method of operating the phase change memory component 1010 further includes performing a rewrite step on at least one memory cell 200 having the second state (as depicted in step 77). The initial current-resistance characteristic function 302 of the memory cell 200 having the second state is converted into a rewriting current-resistance characteristic function (not shown), and the memory cell having a function of rewriting current-resistance characteristics is shown. 200 is set to a third state (as depicted in step 78) to provide phase change memory component 1010 for reading. Where rewrite current - The resistance characteristic function is also essentially a translation function of the initial current-resistance characteristic function 301. For example, the rewrite current-resistance characteristic function can be one of a plurality of offset current-resistance characteristic functions 302 as depicted in FIG.

According to the above embodiment, the present invention provides a method for repairing a phase change memory element by applying a restoring stress to a phase change memory material of a memory cell (because of the number of reset and/or set operations, in the array) Structure, material variation, process conditions, or exposed ambient temperature factors) aging phase change memory material properties, such as the current-resistance characteristic function of the phase change memory material, from the offset state to the initial initial status. In order to solve the problem of the increase of the operating current caused by the aging of the memory material due to the phase change of the memory cell, the problem of the memory cell is even generated.

In addition, the recoverability between the offset current-resistance characteristic function of the phase change memory material and the initial current-resistance characteristic function is utilized to provide a way for the memory cell to access another data. Therefore, the storage density of the data is greatly increased without changing the structure of the phase change memory element.

While the invention has been described above in the preferred embodiments, it is not intended to limit the invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

S51‧‧‧ provides a phase change memory component that contains at least one memory cell with phase change memory material, and this phase change memory material has an offset current-resistance characteristic function

S52‧‧‧Bake process of phase change memory materials

S53‧‧‧Check the step to confirm whether the offset current-resistance characteristic function is converted to the initial current-resistance characteristic function

S54‧‧‧Determine whether to perform another rewrite step on the repaired memory cell

S55‧‧‧ applies a stress current to the phase change memory material of the memory cell, and converts the initial current-resistance characteristic function of the phase change memory material into an offset current-resistance characteristic function.

Claims (8)

A method of repairing a phase change memory component, comprising: providing at least one memory cell, the memory cell comprising a phase change memory material having an initial current-resistance characteristic function; performing a plurality of operation steps, including The memory cell is subjected to a set, a reset, or any combination thereof, and a stress current is applied to the phase change memory material to cause the initial current-resistance characteristic of the phase change memory material. The function converts to a shift current-resistance characteristic function; applying a healing stress to the phase change memory material, including applying a return current to the phase change memory material, causing the phase to change the memory material The offset current-resistance characteristic function is converted into the initial current-resistance characteristic function; wherein the stress current has an upper limit value and a lower limit value, and the return current is substantially one-half of the upper limit value and five points One of the lower limit values; the stress current is substantially between 200 microamperes (μA) and 500 microamperes; the offset current-resistance characteristic function is substantially the current-electricity A translation function characteristic function (translation of function). The method for repairing a phase change memory element according to claim 1, wherein the step of applying the return stress to the phase change memory material comprises: performing a baking process on the phase change memory material, wherein the baking The process has a baking temperature substantially between 300 ° C and 400 ° C, and a baking time substantially between 1 minute and 30 minutes. The method for repairing phase change memory components according to claim 1, wherein the operating steps further comprise: applying an electrical energy, a thermal stress, a mechanical stress, or any combination thereof to the phase change memory material, Converting the initial current-resistance characteristic function of the phase change memory material into the offset current-resistance characteristic function; and the repair method of the phase change memory element further comprises a rewriting step to make the phase change memory The initial current-resistance characteristic function of the material is converted to a re-write current-resistance characteristic function. The method for repairing a phase change memory device according to claim 1, wherein applying the return stress to the phase change memory material further comprises: performing a detecting step to confirm whether the offset current-resistance characteristic function is Converting to the initial current-resistance characteristic function; and if the offset current-resistance characteristic function is not converted to the initial current-resistance characteristic function, applying the return stress to the phase change memory material; the detecting step includes The phase change memory material applies a detection pulse. A method of operating a phase change memory component, comprising: providing a phase change memory component having a plurality of memory cells, wherein each of the memory cells comprises a phase change memory material having an initial current-resistance characteristic function; The memory cell performs a set, a reset, or any of the above groups Applying a stress current to the phase change memory material to convert the initial current-resistance characteristic function of the phase change memory material of at least one of the memory cells into an offset current-resistance characteristic function Setting the memory cell having the offset current-resistance characteristic function to a first state; applying a restoring stress to the at least one memory cell having the first state, including applying a reply to the phase change memory material a current that converts the offset current-resistance characteristic function of the memory material into an initial current-resistance characteristic function; wherein the stress current has an upper limit value and a lower limit value, and the return current is substantially in between Between the upper limit value and one fifth of the lower limit value; the stress current is substantially between 200 microamperes (μA) and 500 microamperes; the offset current-resistance characteristic function is substantially the current-resistance a translation function of the characteristic function; setting the initial current-resistance characteristic function of the memory cells to a second state; and by the first state and the second state, Memory cells in the cell readout data. The method of operating a phase change memory element according to claim 5, wherein the step of applying the restoring stress further comprises: performing a baking process on the memory cell having the first state. Operation of phase change memory components as described in claim 5 The method, wherein the step of converting the initial current-resistance characteristic function of the phase change memory material of at least one of the memory cells to the offset current-resistance characteristic function further comprises: applying an electrical energy to the phase change memory material, a thermal stress, a mechanical stress, or any combination thereof; and the method of operating the phase change memory element further comprises: performing a rewrite step on at least one of the memory cells having the second state, The initial current-resistance characteristic function of the memory cell of the second state is converted into a re-write current-resistance characteristic function, wherein the re-write current-resistance characteristic function is substantially a translation function of the initial current-resistance characteristic function; And setting the memory cell having the function of the rewriting current-resistance characteristic to a third state. The method for operating a phase change memory device according to claim 5, after the applying the stress, further comprising: performing a detecting step to confirm whether the offset current-resistance characteristic function is converted to the initial current a resistance characteristic function; and if the offset current-resistance characteristic function is not converted to the initial current-resistance characteristic function, applying the return stress to the phase change memory material; wherein the detecting step comprises remembering the phase change memory The material applies a detection pulse.