Method for pressure detection based on quantum confinement effect of tie-free finfet

Abstract

This invention relates to the field of compressive stress detection, specifically to a pressure detection method based on the quantum confinement effect of junctionless FinFETs. By measuring the height and width of the nanowire channel in a junctionless FinFET device, the ground state and first excited state energy levels of the lowest two energy levels of the doubly degenerate and quadruple degenerate bands are determined, and the transfer characteristic curve of the device without applied stress is measured to determine the gate voltage-energy conversion relationship. Then, the transfer characteristic curve of the device under applied stress is measured to determine the gate voltage change corresponding to the conductance step of the ground state energy level of the doubly and quadruple degenerate sub-bands. The theoretical separation values ​​of the silicon doubly and quadruple degenerate bands under applied stress are determined. Based on the gate voltage change and the gate voltage-energy conversion relationship, the offset values ​​of the doubly and quadruple degenerate sub-bands caused by stress are calculated, and combined with the theoretical separation values, the applied stress is deduced. This invention effectively improves the accuracy of pressure measurement.

Description

Technical Field

[0001] This invention relates to the field of compressive stress detection, and in particular to a stress detection method based on the quantum confinement effect of junctionless FinFET. Background Technology

[0002] Stress alters the crystal structure of a MOSFET, affecting the mobility of charge carriers (electrons / holes) and causing quantifiable shifts in drain current and threshold voltage. Detecting stress by utilizing the shift in electrical parameters of a MOSFET after stress application is one of the core operating principles of semiconductor stress sensors. Existing MOSFET-based compressive stress sensors mostly convert externally applied stress into changes in the device's threshold voltage or current. For minute compressive stresses, the current change is minimal, and there are various methods for extracting the threshold voltage, which can lead to discrepancies and inaccurate stress measurements, failing to meet the requirements for precise measurement.

[0003] Junctionless FinFETs, a novel type of field-effect transistor, feature consistently high doping concentrations in their source, drain, and channel. They utilize the gate field effect to deplete the channel and control device switching. Since current primarily flows in the center of the channel (bulk transport mode), they are less affected by interface scattering. When the feature size of junctionless FinFETs shrinks to the nanometer scale (around 10 nm), they exhibit significant quantum confinement effects under specific conditions (such as low temperatures), resulting in conduction band splitting into discrete sub-bands. For silicon nanowires, the conduction band bottom splits into two sets of sub-bands: a doubly degenerate and a quadruple degenerate sub-band. This band structure is extremely sensitive to stress. Applying compressive stress causes relative energy shifts in these two sets of sub-bands (valley splitting), and this shift is strictly linearly related to the stress. Compared to a slight change in mobility, even a small stress can cause an observable change in the relative positions of the sub-bands (reflected in changes in the gate voltage difference at the conductance step in the transfer characteristic curve).

[0004] Therefore, by utilizing the correspondence between subband splitting induced by the quantum confinement effect in junctionless FinFET and stress, it is expected to overcome the problems of low sensitivity and susceptibility to threshold voltage drift interference in traditional piezoresistive sensors, and achieve high-precision detection of minute compressive stress. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a pressure detection method based on the quantum confinement effect of junctionless FinFETs. The specific technical solution adopted is as follows: On one hand, the present invention provides a pressure detection method based on the quantum confinement effect of junctionless FinFET, comprising the following steps: The height and width of the nanowire channel in a pre-fabricated junctionless FinFET device were measured along the

[110] crystal orientation. Based on the measured height and width, the ground state energy level and the first excited state energy level of the two sets of sub-bands, double degenerate and quadruple degenerate, separated from the silicon energy level under the quantum confinement of nanowires are determined. The current-voltage transfer characteristic curves of the junctionless FinFET device under no stress were measured to determine the gate voltage values ​​corresponding to the ground state and the first excited state of the double degenerate and quadruple degenerate subbands. Based on the ground state energy level value, the first excited state energy level, and the gate voltage values ​​corresponding to the ground state and the first excited state, the conversion relationship between gate voltage and energy is determined. The current-voltage transfer characteristic curves of the junctionless FinFET device under stress were measured, and the gate voltage values ​​corresponding to the ground state of the double degenerate and quad degenerate subbands under no stress were combined to determine the gate voltage change of the conductance steps corresponding to the two ground state energy levels of the double degenerate and quad degenerate subbands. Determine the theoretical separation values ​​of silicon double and quadruple degenerate bands caused by stress in junctionless FinFET devices; Based on the gate voltage change and the conversion relationship between the gate voltage and energy, the offset values ​​of the double degenerate and quadruple degenerate subbands caused by stress are calculated. The offset values ​​are compared with the theoretical separation values ​​to deduce the magnitude of the applied stress.

[0006] In some possible implementations, the ground state energy level and the first excited state energy level of the two sets of sub-bands separated from the silicon energy level, namely the two-fold degenerate and four-fold degenerate sub-bands, are determined by the following formulas: In the formula: It is Planck's constant. It is a double degenerate energy level and four degenerate energy levels Effective electron mass of subband, two-fold degenerate energy levels Effective electron mass of subband Four-fold degenerate energy levels Effective electron mass of subband m0 is the electron mass; m and n are quantum order numbers. Different integer values ​​of m and n can be used to obtain different energy level positions. The two energy levels with the lowest energy correspond to the ground state and the first excited state.

[0007] In some possible implementations, the conversion relationship between gate voltage and energy is determined, including: The energy values ​​of the ground state level and the first excited state level of the two sets of sub-bands with double degeneracy and quadruple degeneracy are compared respectively to determine the energy interval of the lowest two levels of the double degeneracy and quadruple degeneracy bands separated from the silicon energy level. By comparing the gate voltage values ​​corresponding to the ground state and the first excited state of the double-degenerate and quadruple-degenerate subbands respectively, the gate voltage spacing corresponding to the lowest two energy levels of the double-degenerate and quadruple-degenerate subbands is determined. By comparing the energy interval with the gate voltage interval, the conversion relationship between gate voltage and energy is determined.

[0008] In some possible implementations, the conversion relationship between gate voltage and energy is determined, and the corresponding calculation formula is as follows: In the formula: It is the effective gate capacitance, used to characterize the conversion coefficient between gate voltage and energy. It is Planck's constant. It is the gate voltage spacing corresponding to the lowest two energy levels of the double-degenerate and quadruple-degenerate bands. It represents the energy interval corresponding to the lowest two energy levels of the double-degenerate and quadruple-degenerate bands. It is the effective mass of electrons in the two-fold and four-fold degenerate energy levels that participate in electrical conduction. and weight e represents the electron charge.

[0009] In some possible implementations, the gate voltage change corresponding to the conductance steps of the two ground state energy levels of the doubly degenerate and quadruple degenerate subbands is determined, including: Based on the current-voltage transfer characteristic curves of junctionless FinFET devices under applied stress, the gate voltage values ​​corresponding to the ground states of double-degenerate and quadruple-degenerate subbands are determined. Determine the first gate voltage difference between the gate voltage values ​​corresponding to the ground states of the two-fold degenerate and four-fold degenerate subbands when stress is applied; Determine the second gate voltage difference between the gate voltage values ​​corresponding to the ground states of the two-fold degenerate and four-fold degenerate subbands when no stress is applied; The difference between the first gate voltage difference and the second gate voltage difference is determined as the gate voltage change of the two ground state energy levels corresponding to the conductance steps of the double degenerate and quadruple degenerate subbands.

[0010] In some possible implementations, the theoretical separation values ​​of the silicon doublet and quadruple degenerate bands caused by stress in junctionless FinFET devices are determined, and the corresponding calculation formulas are as follows: In the formula: These are the theoretical values ​​for the separation of silicon double and quadruple degenerate bands caused by stress in junctionless FinFET devices. and These are the deformation potential and shear deformation potential of the silicon conduction band. It is the trace of the strain tensor. These are components of the strain tensor. It is the unit vector in the reciprocal space of the crystal lattice.

[0011] Secondly, the present invention also provides a pressure detection device based on the junctionless FinFET quantum confinement effect, comprising a memory and a processor. The memory is used to store executable computer program code, and the processor is used to call and run the executable computer program code from the memory, causing the device to perform the pressure detection method based on the junctionless FinFET quantum confinement effect as described in the first aspect or any possible implementation thereof.

[0012] The present invention has the following beneficial effects: When compressive stress is applied, the discrete sub-bands with different degeneracy in the silicon nanowire channel shift, and the energy level spacing changes. This is reflected in the change of the conductance step position in the transfer characteristic curve. Therefore, by measuring the height and width of the nanowire channel of the junctionless FinFET device, the ground state energy level and the first excited state energy level of the two sets of degenerate and four-fold degenerate sub-bands separated by the silicon energy level under the quantum confinement of the nanowire are determined. The current-voltage transfer characteristic curve of the device without stress is measured to determine the gate voltage value corresponding to the ground state and the first excited state of the two-fold degenerate and four-fold degenerate sub-bands, and thus determine the conversion relationship between gate voltage and energy. Simultaneously, the current-voltage transfer characteristic curve of the device under applied stress is measured, and combined with the gate voltage values ​​corresponding to the ground states of the two-fold and four-fold degenerate sub-bands when no stress is applied, the gate voltage change of the conductance steps corresponding to the two ground state energy levels of the two-fold and four-fold degenerate sub-bands is determined; the theoretical separation values ​​of the silicon two-fold and four-fold degenerate bands caused by the device under applied stress are determined; based on the gate voltage change and the conversion relationship between gate voltage and energy, the offset values ​​of the two-fold and four-fold degenerate sub-bands caused by stress are calculated, and combined with the theoretical separation values, the applied stress is deduced. This invention only needs to obtain the channel width and height of the junctionless FinFET device, as well as the gate voltage values ​​at the locations of the conductance steps before and after stress application, to accurately calculate the applied compressive stress value. Since the extraction of the conductance step position is more accurate, this invention has higher accuracy than traditional compressive stress sensors based on MOSFET structures (which rely on threshold voltage shift for detection). Attached Figure Description

[0013] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a flowchart illustrating the steps of a pressure detection method based on the junctionless FinFET quantum confinement effect according to an embodiment of the present invention. Figure 2 This is a three-dimensional structural schematic diagram of a junctionless FinFET device according to an embodiment of the present invention; Figure 3 The results of the conductivity step test are from an embodiment of the present invention. Figure 4 This is a transconductance diagram of the test current in an embodiment of the present invention. Detailed Implementation

[0015] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0016] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0017] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0018] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0019] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0020] Although operations or steps are described in a specific order in the accompanying drawings in the embodiments of the present invention, this should not be construed as requiring these operations or steps to be performed in the specific order or serial order shown, or requiring all of the shown operations or steps to be performed to obtain the desired result. In the embodiments of the present invention, these operations or steps may be performed serially; they may be performed in parallel; or a portion of these operations or steps may be performed.

[0021] Furthermore, it is understood that the data involved in the technical solutions of this invention (including but not limited to the data itself, the acquisition or use of the data) shall comply with the requirements of relevant laws, regulations, and provisions. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] The following will describe in detail, with reference to the accompanying drawings, a pressure detection method based on the junctionless FinFET quantum confinement effect provided by an embodiment of the present invention.

[0023] Figure 1 This diagram illustrates the basic flowchart of a pressure detection method based on the junctionless FinFET quantum confinement effect provided by an embodiment of the present invention. Figure 1 As shown, the method specifically includes the following steps: Step S1: Measure the height and width of the nanowire channel of the pre-fabricated junctionless FinFET device.

[0024] A junctionless FinFET device was fabricated on a silicon substrate. The cross-sectional morphology of the fabricated junctionless FinFET device was characterized, and the height and width of the nanowire channel of the junctionless FinFET device were measured.

[0025] In one possible implementation, such as Figure 2 As shown, a single-channel junctionless FinFET device is fabricated on an SOI substrate 1 with a

[100] crystal orientation, with the channel direction along the

[110] direction to enable it to exhibit quantum confinement effects. This single-channel junctionless FinFET device includes a source terminal 3 and a drain terminal 4, a single nanowire channel 2 connected between the source terminal 3 and the drain terminal 4, a gate 5 located between the source terminal 3 and the drain terminal 4, and a source electrode 6, a drain electrode 7, and a gate electrode 8. The nanowire channel 2 passes through the gate 5, such that the gate 5 surrounds or covers the middle region of the nanowire channel 2. To ensure that the quantum confinement effect is observed at room temperature, the size of the nanowire channel 2 must satisfy 10nm ≤ W, H ≤ 15nm. The source electrode 6, drain electrode 7, and gate electrode 8 are respectively disposed on the source terminal 3, drain terminal 4, and gate electrode 5 and electrically connected. Furthermore, a planarized passivation layer 9 covers the device and exposes the source electrode 6, drain electrode 7, and gate electrode 8 for external connections.

[0026] To ensure the observation of the quantum confinement effect at room temperature while reducing the difficulty of fabrication, the size of the nanowire channel 2 must satisfy 10nm ≤ W, H ≤ 15nm. Furthermore, to ensure sufficient mechanical strength of the device during the detection of compressive stress, a glass through-hole encapsulation technique is used. The sensor is inverted and encapsulated on the substrate, with the compressive stress acting on the back of the device and transmitted to the sensitive area of ​​the nanowire channel 2.

[0027] The cross-sectional morphology of the single-channel junctionless FinFET device prepared above was characterized, and the height H and width W of the nanowire channel 2 were accurately measured, so that pressure detection could be realized based on the height H and width W.

[0028] Step S2: Based on the measured height and width, determine the ground state energy level and the first excited state energy level of the two sets of sub-bands, double degenerate and quadruple degenerate, separated from the silicon energy level under the quantum confinement of nanowires.

[0029] The bulk transport characteristics of junctionless FinFETs make their quantum confinement effect more obvious, and the significant degeneracy of subband splitting can be easily observed in the transfer characteristic curve. After applying compressive stress to the surface of the junctionless FinFET, energy shifts of subbands with different degeneracy will occur. This phenomenon can be used to accurately calculate the magnitude of the applied compressive stress.

[0030] To accurately calculate the applied compressive stress, this embodiment determines the ground state energy level and the first excited state energy level of the two sets of sub-bands, which are doubly degenerate and quadruple degenerate, in the channel region based on the measured height and width.

[0031] In one possible implementation, based on the measured height H and width W, the ground state energy levels of the two sets of sub-bands, one double-degenerate and the other quadruple-degenerate, separated from the silicon energy level under quantum confinement in the height and width directions of the nanowire are calculated. and and the first excited state energy level and The corresponding calculation formula is: (1.1) in: It is Planck's constant, m * yes and The effective electron mass of the subband is here. , m0 is the electron mass; m and n are quantum order numbers. Different integer values ​​of m and n can be used to obtain different energy level positions. The two energy levels with the lowest energy correspond to the ground state and the first excited state.

[0032] Step S3: Measure the current-voltage transfer characteristic curve of the junctionless FinFET device when no stress is applied, and determine the gate voltage values ​​corresponding to the ground state and the first excited state of the double degenerate and quadruple degenerate subbands.

[0033] Without applying stress, the junctionless FinFET device was tested to obtain its current-voltage transfer characteristic curve. Then, based on this transfer characteristic curve, the gate voltage values ​​corresponding to the ground state and the first excited state of the double-degenerate and quadruple-degenerate subbands were determined.

[0034] Specifically, when measuring the current-voltage transfer characteristic curve of a junctionless FinFET device under no stress, the junctionless FinFET device is connected to a semiconductor parameter analyzer. Under no stress, the potentials of the source electrode 6 and drain electrode 7 are fixed, such as by grounding the source electrode. A fixed small bias voltage (e.g., fixed at 50mV) is applied to the drain electrode, and the voltage V of the gate electrode 8 is varied within a preset range. G For example, the voltage is gradually increased from 0V to 1V, and the leakage current of the drain electrode 7 is recorded in real time. The voltage V of the gate electrode 8 is used as the reference. G Plotting the curve with the horizontal axis as the abscissa and the leakage current of the drain electrode 7 as the vertical axis yields the current-voltage transfer characteristic curve of the junctionless FinFET device when no stress is applied.

[0035] The transconductance curve is obtained by differentiating the current-voltage transfer characteristic curve of a junctionless FinFET device under no applied stress. Since the conductance step height of a quadruple-degenerate device is twice that of a double-degenerate device, this is reflected in the transconductance curve as a more significant transconductance peak (i.e., larger under-peak area or height) compared to the double-degenerate peak. Based on this characteristic, and combined with the scanning order of gate voltage from low to high (energy from low to high), the characteristic peaks on the transconductance curve are classified and ordered. Among the classified characteristic peaks, such as... Figure 3 As shown, the two lowest gate voltage peaks in the two-fold degenerate subband sequence and the two lowest gate voltage peaks in the four-fold degenerate subband sequence are selected, respectively. The horizontal coordinates corresponding to these four peaks are read and determined as the gate voltage positions of the ground state and the first excited state of the two-fold and four-fold degenerate subbands, respectively, thus obtaining the gate voltage values ​​corresponding to the ground state and the first excited state of the two-fold degenerate subband. and And the gate voltage values ​​corresponding to the ground state and the first excited state of the four-fold degenerate band. and .

[0036] Step S4: Based on the ground state energy level value, the first excited state energy level, and the gate voltage values ​​corresponding to the ground state and the first excited state, determine the conversion relationship between gate voltage and energy.

[0037] The relationship between gate voltage and energy is quantified based on the ground state energy level values ​​corresponding to the two sets of sub-levels (double degenerate and quadruple degenerate), the first excited state energy level, and the gate voltage values ​​corresponding to the ground state and the first excited state.

[0038] In one possible implementation, determining the conversion relationship between gate voltage and energy includes: First, the ground state energy level values ​​and the first excited state energy level of the two sets of sub-bands, one double degenerate and one quadruple degenerate, are compared to determine the energy interval between the lowest two energy levels of the double degenerate and quadruple degenerate bands separated from the silicon energy level.

[0039] Specifically, corresponding to the structural parameters of the fabricated device, the energy gap between the ground state energy level and the first excited state energy level of each of the two sets of sub-levels is calculated, and the corresponding calculation formula is as follows: (1.2) (1.3) in: It is the energy interval between the two lowest energy levels of the double degenerate band; It is the energy interval between the two lowest energy levels of the quadruple degenerate band.

[0040] Secondly, the gate voltage values ​​corresponding to the ground state and the first excited state of the bi-degenerate and quad-degenerate subbands are compared to determine the gate voltage spacing corresponding to the lowest two energy levels of the bi-degenerate and quad-degenerate subbands.

[0041] Specifically, the gate voltage values ​​corresponding to the ground state and the first excited state of the two degenerate bands are... and The comparisons were made, and the gate voltage values ​​corresponding to the ground state and the first excited state of the quadruple degenerate band were compared. and By comparison, the gate voltage spacing corresponding to the lowest two energy levels of the double-degenerate and quad-degenerate bands is determined. and The corresponding calculation formula is: (1.4) (1.5) Finally, the energy gap and the gate voltage gap are compared to determine the conversion relationship between gate voltage and energy.

[0042] The relationship between the gate voltage interval and the energy interval is quantified based on the energy gap between the ground state level and the first excited state level of each of the two sets of sub-levels, as well as the gate voltage interval.

[0043] In one possible implementation, based on the energy interval between the ground state level and the first excited state level of each of the two sets of sub-levels. and and gate voltage spacing and The conversion relationship between gate voltage and energy is determined, and the corresponding calculation formula is as follows: (1.6) In the formula: It is the effective gate capacitance, used to characterize the conversion coefficient between gate voltage and energy. It is Planck's constant. It is electronic charge. It is the gate voltage spacing corresponding to the lowest two energy levels of the double-degenerate and quadruple-degenerate bands. It represents the energy interval corresponding to the lowest two energy levels of the doubly and quadruplely degenerate bands. When Values and Value , and when Values and Value At that time, two gate capacitances C can be obtained. ox The value of the gate capacitance is taken here as the average of the two values. This is to reduce calculation errors. It is the effective electron mass, which is taken as... and weight The value is approximately 0.402m0. It should be noted that under compressive stress, and Changes will occur, but considering the small applied compressive stress (<100 MPa), the change in effective mass due to the compressive stress is negligible. Gate effective capacitance C o In addition to the gate's own MOS capacitance, this method also includes the parasitic capacitance between the gate and the source electrode 6 and the drain electrode 7. The gate capacitance C calculated by this method... ox The results are more accurate than those calculated directly using the gate area and gate dielectric layer thickness.

[0044] Step S5: Measure the current-voltage transfer characteristic curve of the junctionless FinFET device under stress and compare it with the current-voltage transfer characteristic curve under no stress to determine the gate voltage change of the two ground state energy levels corresponding to the conductance steps of the double degenerate and quadruple degenerate subbands.

[0045] Stress is applied to the top side of the fabricated junctionless FinFET device, and the stress is transmitted downwards to the nanowire channel 2. By changing the potential V of the gate electrode 8, the stress is controlled. GThe leakage current of the drain electrode 7 after stress is applied is observed, and the current-voltage transfer characteristic curve of the junctionless FinFET device without stress is obtained in the same way as the current-voltage transfer characteristic curve of the junctionless FinFET device without stress is obtained. The two current-voltage transfer characteristic curves are compared to determine the gate voltage position change of the two ground state energy levels corresponding to the conductance steps of the double degenerate and quadruple degenerate subbands.

[0046] In one possible implementation, the gate voltage change corresponding to the conductance step of the two ground state levels of the doubly degenerate and quadruple degenerate subbands is determined, including: First, based on the current-voltage transfer characteristic curves of the junctionless FinFET device under applied stress, the gate voltage values ​​corresponding to the ground states of the double degenerate and quadruple degenerate subbands are determined.

[0047] Specifically, based on the current-voltage transfer characteristic curves of the junctionless FinFET device under no applied stress, the gate voltage values ​​corresponding to the ground states of the double-degenerate and quadruple-degenerate subbands are obtained. and Similarly, based on the current-voltage transfer characteristic curves of junctionless FinFET devices under applied stress, the gate voltage values ​​corresponding to the ground states of the double-degenerate and quadruple-degenerate subbands were determined. and .

[0048] Secondly, determine the first gate voltage difference between the gate voltage values ​​corresponding to the ground states of the double-degenerate and quadruple-degenerate subbands when stress is applied.

[0049] Specifically, based on the gate voltage values ​​corresponding to the ground states of the two-fold and four-fold degenerate subbands under applied stress. and Determine the first gate voltage difference - .

[0050] Next, the second gate voltage difference between the gate voltage values ​​corresponding to the ground states of the double degenerate and quadruple degenerate subbands when no stress is applied is determined.

[0051] Specifically, based on the gate voltage values ​​corresponding to the ground states of the two-fold and four-fold degenerate subbands when no stress is applied. and Determine the second gate voltage difference - .

[0052] Finally, the difference between the first gate voltage difference and the second gate voltage difference is determined as the gate voltage change of the two ground state energy levels corresponding to the conductance steps of the double degenerate and quadruple degenerate subbands.

[0053] Specifically, such as Figure 3 and Figure 4 As shown, the relative height of the conductance step and the relative value of transconductance both change before and after applying compressive stress. Therefore, based on the first gate voltage difference... - and the second gate voltage difference - The gate voltage change corresponding to the conductance step of the two ground state energy levels of the doubly degenerate and quadruple degenerate subbands is determined, and the corresponding calculation formula is as follows: (1.7) In the formula: It is the gate voltage change corresponding to the conductance step of the two ground state energy levels of the doubly degenerate and quadruple degenerate subbands.

[0054] Step S6: Determine the theoretical separation values ​​of the silicon double and quadruple degenerate bands caused by stress on the junctionless FinFET device.

[0055] After applying compressive stress, the overall energy of the two-fold degenerate subband shifts downward relative to the four-fold degenerate subband. The theoretical calculations show the numerical values ​​of the shift in silicon's two-fold and four-fold degenerate subbands caused by the compressive stress.

[0056] In one possible implementation, the theoretical separation values ​​of the silicon doublet and quadruple degenerate bands caused by stress in a junctionless FinFET device are determined, and the corresponding calculation formula is as follows: (1.8) In the formula: These are the theoretical values ​​for the separation of silicon double and quadruple degenerate bands caused by stress in junctionless FinFET devices. and These are the deformation potential and shear deformation potential of the silicon conduction band. It is the trace of the strain tensor. These are components of the strain tensor. It is a unit vector in the reciprocal space of the crystal lattice. It can calculate the compressive stress in the

[100] direction. A 1 GPa compressive stress causes a double and quadruple degenerate band shift of 90 meV. The shift is proportional to the stress magnitude, and the shift energy value is proportional to the compressive stress. It is independent of the stress inside the junctionless FinFET and has high calculation accuracy.

[0057] Step S7: Based on the change in gate voltage and the conversion relationship between gate voltage and energy, calculate the offset values ​​of the double degenerate and quadruple degenerate subbands caused by stress, compare the offset values ​​with the theoretical separation values, and deduce the magnitude of the applied stress.

[0058] The magnitude of the applied stress is calculated by comparing the gate voltage change obtained from the experiment with the value of the stress-induced shift between the two sets of sub-band levels, and then compared with the theoretical separation value to infer the magnitude of the applied stress.

[0059] In one possible implementation, the gate voltage change is substituted into the formula (1.6) corresponding to the conversion relationship between gate voltage and energy, and the formula (1.8) corresponding to the theoretical separation values ​​of the silicon double and quadruple degenerate bands caused by stress in a junctionless FinFET device. The numerical value can be obtained from the compressive stress, which is the change in gate voltage interval under stress as measured experimentally. Calculate the numerical shift of the two sets of subband levels caused by stress. Numerical separation from theory By comparison, the magnitude of the strain tensor generated by the applied stress can be deduced from formula (1.8), and the actual applied stress can be obtained using Hooke's law. In this calculation process, the theoretically obtained compressive stress is the applied compressive stress and is independent of the internal stress of the junctionless FinFET device.

[0060] Based on the above technical solution, since the sub-band level shift caused by small compressive stress is large, it is reflected in the large change of the gate voltage position corresponding to the ground state conductance step. Therefore, compared with the traditional method of calculating compressive stress by using the change of current or threshold voltage of FinFET under stress, the solution proposed in this embodiment has higher detection accuracy.

[0061] Based on the same inventive concept, embodiments of the present invention also provide a pressure detection device based on the junctionless FinFET quantum confinement effect. The device includes: a memory, a processor, and computer program code stored in the memory and running on the processor. When the processor executes the computer program code, the device can perform any of the aforementioned pressure detection methods based on the junctionless FinFET quantum confinement effect.

[0062] It should be noted that the device provided in the above embodiments is only an example of the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A pressure detection method based on the quantum confinement effect of junctionless FinFET, characterized in that, Includes the following steps: The height and width of the nanowire channel in a pre-fabricated junctionless FinFET device were measured along the [110] crystal orientation. Based on the measured height and width, the ground state energy level and the first excited state energy level of the two sets of sub-bands, double degenerate and quadruple degenerate, separated from the silicon energy level under the quantum confinement of nanowires are determined. The current-voltage transfer characteristic curves of the junctionless FinFET device under no stress were measured to determine the gate voltage values ​​corresponding to the ground state and the first excited state of the double degenerate and quadruple degenerate subbands. Based on the ground state energy level value, the first excited state energy level, and the gate voltage values ​​corresponding to the ground state and the first excited state, the conversion relationship between gate voltage and energy is determined. The current-voltage transfer characteristic curves of the junctionless FinFET device under stress were measured, and the gate voltage values ​​corresponding to the ground state of the double degenerate and quad degenerate subbands under no stress were combined to determine the gate voltage change of the conductance steps corresponding to the two ground state energy levels of the double degenerate and quad degenerate subbands. Determine the theoretical separation values ​​of silicon double and quadruple degenerate bands caused by stress in junctionless FinFET devices; Based on the gate voltage change and the conversion relationship between the gate voltage and energy, the offset values ​​of the double degenerate and quadruple degenerate subbands caused by stress are calculated. The offset values ​​are compared with the theoretical separation values ​​to deduce the magnitude of the applied stress.

2. The pressure detection method based on the junctionless FinFET quantum confinement effect according to claim 1, characterized in that, The ground state energy level and the first excited state energy level of the two sets of sub-bands separated from the silicon energy level, namely the two-fold degenerate and four-fold degenerate sub-bands, are determined by the following calculation formulas: In the formula: It is Planck's constant. It is a double degenerate energy level and four degenerate energy levels Effective electron mass of subband, two-fold degenerate energy levels Effective electron mass of subband Four-fold degenerate energy levels Effective electron mass of subband m0 is the electron mass; m and n are quantum order numbers. Different integer values ​​of m and n can be used to obtain different energy level positions. The two energy levels with the lowest energy correspond to the ground state and the first excited state.

3. The pressure detection method based on the junctionless FinFET quantum confinement effect according to claim 1, characterized in that, Determine the conversion relationship between gate voltage and energy, including: The energy values ​​of the ground state level and the first excited state level of the two sets of sub-bands with double degeneracy and quadruple degeneracy are compared respectively to determine the energy interval of the lowest two levels of the double degeneracy and quadruple degeneracy bands separated from the silicon energy level. By comparing the gate voltage values ​​corresponding to the ground state and the first excited state of the double-degenerate and quadruple-degenerate subbands respectively, the gate voltage spacing corresponding to the lowest two energy levels of the double-degenerate and quadruple-degenerate subbands is determined. By comparing the energy interval with the gate voltage interval, the conversion relationship between gate voltage and energy is determined.

4. The pressure detection method based on the junctionless FinFET quantum confinement effect according to claim 3, characterized in that, The conversion relationship between gate voltage and energy is determined by the following formula: In the formula: It is the effective gate capacitance, used to characterize the conversion coefficient between gate voltage and energy. It is Planck's constant. It is the gate voltage spacing corresponding to the lowest two energy levels of the double-degenerate and quadruple-degenerate bands. It represents the energy interval corresponding to the lowest two energy levels of the double-degenerate and quadruple-degenerate bands. It is the effective mass of electrons in the two-fold and four-fold degenerate energy levels that participate in electrical conduction. and weight e represents the electron charge.

5. The pressure detection method based on the junctionless FinFET quantum confinement effect according to claim 1, characterized in that, Determine the gate voltage change corresponding to the conductance step of the two ground state energy levels in double-degenerate and quadruple-degenerate subbands, including: Based on the current-voltage transfer characteristic curves of junctionless FinFET devices under applied stress, the gate voltage values ​​corresponding to the ground states of double-degenerate and quadruple-degenerate subbands are determined. Determine the first gate voltage difference between the gate voltage values ​​corresponding to the ground states of the two-fold degenerate and four-fold degenerate subbands when stress is applied; Determine the second gate voltage difference between the gate voltage values ​​corresponding to the ground states of the two-fold degenerate and four-fold degenerate subbands when no stress is applied; The difference between the first gate voltage difference and the second gate voltage difference is determined as the gate voltage change of the two ground state energy levels corresponding to the conductance steps of the double degenerate and quadruple degenerate subbands.

6. The pressure detection method based on the junctionless FinFET quantum confinement effect according to claim 1, characterized in that, The theoretical separation values ​​of the silicon doublet and quadruple degenerate bands caused by stress in junctionless FinFET devices are determined, and the corresponding calculation formulas are as follows: In the formula: These are the theoretical values ​​for the separation of silicon double and quadruple degenerate bands caused by stress in junctionless FinFET devices. and These are the deformation potential and shear deformation potential of the silicon conduction band. It is the trace of the strain tensor. These are components of the strain tensor. It is the unit vector in the reciprocal space of the crystal lattice.

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