DE202022103080U1 - A novel 2-D TFET based on Si0.8Ge0.2 source gate for detection of breast cancer cell lines - Google Patents

Abstract

A novel dual gate Si _0.8 Ge _0.2 breast cancer cell line detection device, the device comprising:
a source layer with a length of 17 nm doped with the arsenic dopant at a concentration of 1.5×10 ²⁰ ;
a pocket layer with a length of 5 nm doped with the boron dopant at a concentration of 2 × 10 ¹⁹ ,
a channel layer with a length of 13 nm doped with the arsenic dopant at a concentration of 2 × 10 ¹⁴ ,
a drain layer with a length of 25 nm doped with the boron dopant at a concentration of 3×10 ¹⁷ ;
a plurality of HfO ₂ layers 1 nm thick and 22 nm long used as gate oxide on the top and bottom of the device;
a plurality of SiO ₂ layers with a width of 2 nm and a height of 5 nm arranged over the HfO ₂ layer; and
a plurality of gate metals disposed over the SiO ₂ layer on both the top and bottom, with nanovoids in the device each having a width of 5 nm.

Description

FIELD OF THE INVENTION

The present disclosure relates to the field of detection of breast cancer cell lines using a sensor. More particularly, the present disclosure relates to a novel dual gate Si _0.8 Ge _0.2 based 2-D TFET for detection of breast cancer cell lines.

BACKGROUND OF THE INVENTION

Sensors are used in various areas, e.g. B. in biomedicine, environmental monitoring systems and many others. As sensors are used in various industries, this is an important research topic, especially in the field of medicine, since detecting a disease at an early stage is important for curing the disease, and one such disease is cancer that is at an early stage must be recognized for a quick diagnosis of the disease.

There are different types of cancer such as breast and lung cancer, etc. In women, breast cancer is the most common, and timely detection and treatment of this disease is necessary to get rid of it. The technologies commonly used to detect this disease are X-ray mammography and magnetic resonance imaging (MRI). However, these detection techniques are time-consuming, expensive and dependent on hospitals, and one of the major disadvantages is that these technologies require skilled technicians and may not be available in remote areas.

To overcome the above disadvantages, FET (field effect transistor) based sensors have been introduced, which offer high sensitivity, are inexpensive and also consume little power. The most common FET-based sensor is the MOSFET (Metal Oxide Semiconductor Field Effect Transistor). However, as the MOSFET devices become smaller and smaller, the energy density increases because the supply voltage is not scalable, and this creates many inevitable problems in the MOSFET, such as: B. the lowering of the drain barrier, the hot carrier effect and many others.

Therefore, a replacement for MOSFETs is needed, whereby the tunnel field effect transistor can be used as a replacement for MOSFETs. It has recently been extensively researched as a replacement and has several advantages such as steep subthreshold slope, immunity to short channel effects, and low leakage current. The drain current of the TFET can be changed by changing the dielectric between the metal gate and the gate oxide material, which can be used to detect malignant breast cancer tissue.

In view of the foregoing, it is clear that a novel device is needed to detect double-gated Si _0.8 Ge _0.2 breast cancer cell lines.

SUMMARY OF THE INVENTION

The present disclosure relates to a novel dual gate Si _0.8 Ge _0.2 breast cancer cell detection device. This disclosure proposes a dual-gate Si _0.8 Ge _0.2 breast cancer cell detector, which is a biosensor for detecting breast cancer cells (HS578t, MDA-MB-231, MCF7, T47D), where the source of the biosensor is a low- band gap, namely Si _0.8 Ge _0.2 . The pocket of the biosensor is partially Si _0.8 Ge _0.2 and partially silicon conductive, with the channel and drain of the proposed device being silicon to reduce the quiescent current of the device. The proposed biosensor device was made using the exemplary properties of the TEFT, such as. B. low off current, high I _ons /I _off and high sub-threshold swing (SS) designed and developed. The structure of the proposed biosensor consists of two nanogaps on the top and bottom, which are used to increase the sensitivity of the cancer cell lines. First, an analytical modeling of the proposed biosensor is performed and then the modeling results are compared with the simulated results, where in the analytical model the effects of the charge present on the cancer cells on the electrical parameters of the device are studied in detail. The sensitivity of the proposed biosensor is studied for various neutral cancerous and non-tumorigenic healthy cells (MCF-10A), and then the effects of the negatively and positively charged cancerous and non-tumorigenic cells on the sensitivity and the threshold voltage of the proposed sensor are investigated examined. The thermal stability of the The proposed biosensor is studied by varying the temperature from 215 K to 400 K, so that it can be used at any temperature. All simulations were carried out in 2D Synopsys sentaurus TCAD. The results show that the proposed biosensor exhibits high sensitivity when the biosensor's nanogaps are filled with 20%, 40%, 60%, 80%, and 100% cancer cells with different dielectric constants (K = 22.5, 24.4, 27.1, and 32). are. The proposed biosensor has also been shown to be able to detect the charge on cancer cells residing in the device's nanoholes.

The present disclosure aims to provide a novel Si _0.8 Ge _0.2 doped device for double gated breast cancer cell line detection. The device comprises: a source layer having a length of 17 nm and doped with the arsenic dopant at a concentration of 1.5×10 ²⁰ ; a pocket layer with a length of 5 nm doped with the boron dopant at a concentration of 2×10 ¹⁹ ; a channel layer with a length of 13 nm doped with the arsenic dopant at a concentration of 2×10 ¹⁴ ; a drain layer with a length of 25 nm doped with the boron dopant at a concentration of 3 × 10 ¹⁷ , a plurality of HfO ₂ layers with a thickness of 1 nm and a length of 22 nm designated as Gate oxide used on the top and bottom of the device; a plurality of SiO ₂ layers with a width of 2 nm and a height of 5 nm arranged over the HfO ₂ layer; and a plurality of gate metals disposed over the SiO ₂ layer on both top and bottom surfaces, wherein nanovoids in the device are each 5 nm wide.

An object of the present disclosure is to provide a novel dual gate Si _0.8 Ge _0.2 sourced breast cancer cell line detection device.

Another aim of the present disclosure is to use the properties of the tunnel field effect transistor (TFET) for the design and development of the proposed biosensor.

Another aim of the present disclosure is to develop an analytical model of the proposed biosensor and to compare the obtained results with the simulation results.

Another aim of the present disclosure is to increase the sensitivity of the proposed biosensor for the detection of cancer cell lines.

Another objective of the present disclosure is to study the sensitivity of the proposed biosensor for various neutral cancerous and non-tumorigenic healthy cells and to further study the effects of negatively and positively charged cancer cells on the sensitivity and threshold voltage of the proposed biosensor.

Another aim of the present disclosure is to investigate the thermal stability of the proposed biosensor.

In order to further clarify the advantages and features of the present disclosure, a more detailed description of the invention is provided by reference to specific embodiments that are illustrated in the accompanying figures. It is understood that these figures represent only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention. The invention will be described and illustrated with additional specificity and detail with the accompanying figures.

character list

• 1 ein Blockdiagramm eines neuartigen Dual-Gate-Si_0.8Ge_0.2 -sourced-Brustkrebszelllinien-Detektionsgerätes gemäß einer Ausführungsform der vorliegenden Offenbarung zeigt;
• 2 den schematischen Aufbau der vorgeschlagenen TFET-Biosensorvorrichtung gemäß einer Ausführungsform der vorliegenden Offenbarung zeigt; und
• 3 die schematische Struktur des vorgeschlagenen TFET-Biosensors mit verschiedenen Bereichen für die analytische Modellierung gemäß einer Ausführungsform der vorliegenden Offenbarung zeigt.

These and other features, aspects, and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying figures, in which like characters represent like parts throughout the figures, wherein:

• 1 Figure 12 shows a block diagram of a novel dual-gate Si _0.8 Ge _0.2 -sourced breast cancer cell line detection device according to an embodiment of the present disclosure;
• 2 shows the schematic structure of the proposed TFET biosensor device according to an embodiment of the present disclosure; and
• 3 12 shows the schematic structure of the proposed TFET biosensor with different regions for analytical modeling according to an embodiment of the present disclosure.

Those skilled in the art will understand that the elements in the figures are presented for simplicity and are not necessarily drawn to scale. For example, the flow charts illustrate the method of key steps to enhance understanding of aspects of the present disclosure. Furthermore, one or more components of the device may be represented in the figures by conventional symbols and the figures show only the specific details relevant to an understanding of the embodiments of the present disclosure, in order not to obscure the figures with details overload that are readily apparent to those skilled in the art familiar with the present specification.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the invention, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe the same. It should be understood, however, that no limitation on the scope of the invention is intended, and such changes and further modifications to the illustrated system and such further applications of the principles of the invention set forth therein are contemplated as would occur to those skilled in the art invention would normally come to mind.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be limiting.

When this specification refers to "an aspect," "another aspect," or the like, it means that a particular feature, structure, or characteristic described in connection with the embodiment is present in at least one embodiment included in the present disclosure. Therefore, the phrases "in one embodiment," "in another embodiment," and similar phrases throughout this specification may or may not all refer to the same embodiment.

The terms "comprises," "including," or other variations thereof are intended to cover non-exclusive inclusion such that a method or method that includes a list of steps includes not only those steps, but may also include other steps that are not expressly stated or pertaining to any such process or method. Likewise, any device or subsystem or element or structure or component preceded by "comprises...a" does not, without further limitation, exclude the existence of other devices or other subsystem or other element or other structure or other component or additional device or additional subsystems or additional elements or additional structures or additional components.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The system, methods, and examples provided herein are for purposes of illustration only and are not intended to be limiting.

Embodiments of the present disclosure are described in detail below with reference to the attached figures.

1 Figure 12 shows a block diagram of a novel Si _0.8 Ge _0.2 doped device for detecting breast cancer cell lines in accordance with an embodiment of the present disclosure. The device 100 has a source layer 102 with a length of 17 nm and is doped with the arsenic dopant at a concentration of 1.5 x 10 ²⁰ .

In one embodiment, a pocket layer 104 is 5 nm in length and doped with the boron dopant at a concentration of 2×10 ¹⁹ .

In one embodiment, a channel layer 106 has a length of 13 nm and is doped with the arsenic dopant at a concentration of 2 x 10 ¹⁴ .

In one embodiment, a drain layer 108 is 25 nm in length and is doped with the boron dopant at a concentration of 3×10 ¹⁷ .

In one embodiment, a plurality of HfO ₂ layers 110 with a thickness of 1 nm and a length of 22 nm are used as the gate oxide on the top and bottom of the device.

In one embodiment, a plurality of SiO ₂ layers 112 with a width of 2 nm and a height of 5 nm are arranged over the HfO ₂ layer.

In one embodiment, a plurality of gate metals 114 are disposed over the SiO ₂ layer on both the top and bottom, with nanovoids in the device each having a width of 5 nm.

In one embodiment, the device 100 consists of 20 nm Si _0.8 Ge _0.2 and 50 nm silicon, with the thickness of Si and Ge being 10 nm.

In one embodiment, a tunnel gate 116 consisting of gate metal (M1) 114 with a work function of 3.75 eV is formed at the top and bottom of the device, and the length of this tunnel gate is 11 nm, with the top and bottom nanogaps of the tunnel gate being one have a length of 10 nm.

In one embodiment, an auxiliary gate 118 at the top of the device consists of gate metal (M2) 114, which has a work function of 5.0 eV, and the auxiliary gate has a length of 6 nm, with the nanogap of the auxiliary gate having a length of 5 nm .

In one embodiment, an area of the total nanogap area for the cancer cells is 100 nm ² in the case of a tunnel gate nanogap and 25 nm ² in the case of an assist gate nanogap.

In one embodiment, the gate oxide, HfO ₂ layer 110, is extended from the drain layer side so that it can act as a spacer to increase the electric field toward the center of the device.

In one embodiment, the SiO ₂ layer 112 is used as the gate metal support because it has a low dielectric constant compared to HfO ₂ , making the developed device more sensitive to the dielectric constant of the cancer cells and thus the effects of the oxide support on the inrush current are lower.

In one embodiment, an analytical model of the proposed device is developed, in which the effects of the charge present on the cancer cells on the electrical parameters of the device are studied in detail, and then the analytical results are compared with the results obtained by performing the simulation of the proposed device are achieved, compared and verified.

In one embodiment, the sensitivity of the proposed device to various neutral cancerous and non-tumorigenic healthy cells is examined, and then the effects of the negatively and positively charged cells on the sensitivity and threshold voltage of the proposed device are examined.

In one embodiment, a thermal stability study is performed on the proposed device by varying the temperature from 215K to 400K.

2 12 shows the schematic structure of the proposed TFET biosensor according to an embodiment of the present disclosure. The biosensor consists of 20 nm Si _0.8 Ge _0.2 which has a bandgap of 1.028 eV and the biosensor also consists of 50 nm silicon with a thickness of 10 nm each. The source (Ls) and channel (Lc) lengths are 17 nm and 13 nm, and both are doped with the dopant arsenic, which has a concentration of 1.5 × 10 ²⁰ cm ^-3 and 2 × 10 ¹⁴ cm ^-3 . The length of the pocket (Lp) and the drain (Ld) are 5 nm and 25 nm, respectively, and both are doped with the dopant boron, which has a concentration of 2×10 ¹⁹ cm ^-3 and 3×10 ¹⁷ . The biosensor device consists of two HfO ₂ layers, one on the bottom and one on top of the source, pocket, channel and drain portions or layers, with the HfO ₂ layer having a thickness of 1 nm and has a length of 22 nm and is used as a gate oxide. Above this HfO ₂ layer is vertically top and bottom a SiO ₂ layer 2 nm wide and 5 nm high. Gate metals are then deposited over these SiO ₂ layers, with M1 and M2 at the top and M2 at the bottom only M1 can be placed, resulting in the formation of a nanovoid in the device with a width (W) of 5 nm. The SiO ₂ layer is used as a carrier for the gate Metal is used because it has a lower dielectric constant compared to HfO ₂ , which makes the biosensor more sensitive to the dielectric constant of the cancer cell and the influence of the oxide support on the inrush current is smaller. At the top are the tunnel gate and the auxiliary gate, at the bottom only the tunnel gate. The tunnel gates both top and bottom are made of metal M1 and have a length of 11 nm. The auxiliary gate is made of metal M2 and have a length of 6 nm. The nanogap of the tunnel gate has a length of 10 nm and the length of the nanogap of the auxiliary gate is 5 nm. The gate oxide, ie the HfO ₂ layer, is extended on the drain side so that it acts as a spacer that increases the electric field towards the center of the device, which contributes to the inrush current of the sensor. The area of the tunnel gate nanogaps is 100 nm ² and the area of the auxiliary gate nanogaps is 25 nm ² .

The simulation of the proposed biosensor device is performed in Synopsys sentaurus TCAD 2019.09 using a non-local BTBT model to estimate the BTBT at the source-channel junction. The proposed biosensor device has a heterostructure with an abrupt heterojunction. Ge and Si are used in the device, which have an indirect band gap in which the phenomenon-assisted tunneling process dominates, and the non-local BTBT model is able to simulate this. The BTBT model is also able to capture the influence of the density of states and the occupied levels in the source channel region. The model can also capture the changes in electric field and tunneling rate over the tunnel length of the device. The model is used for the simulation of the proposed device as it is able to handle the high accuracy for the heavily doped reverse-biased tunnel junction.

3 12 shows the schematic structure of the proposed TFET biosensor with different regions for analytical modeling according to an embodiment of the present disclosure. First, an analytical model of the proposed biosensing device is constructed by examining the effect of the charge present on the cancer cells on the electrical parameters of the device, finding expressions for the surface potential, depletion region width, electric field, and drain current.

As shown in the figure, there are nine different regions into which the proposed biosensor device can be divided, these regions being 1, 2, 3, 4, 5, 6, 7, 8 and 9 and having lengths L ₁ , L , respectively ₂ , L ₃ , L ₄ , L ₅ , L ₆ , L ₇ , L ₈ , and L ₉ .

The analytical model of the proposed TFET biosensor is shown below, obtaining the surface potential expression, the depletion region width, the electric field expression, and the drain current expression.

The expression for the surface potential

The power distribution of the device can be solved by applying the 2-D Poisson equation in the nine regions, with Equation (1) below: $$\frac{{\partial }^2{\psi }_i\left(x,y\right)}{\partial x^2}+\frac{{\partial }^2{\psi }_i\left(x,y\right)}{\partial y^2}=-\frac{q{N}_i}{e_i}$$

In it, Ψi(x,y) stands for the 2-D electrostatic potential, “i” for the nine different regions, Ni for the dopant concentration in the source, channel, and drain region, and εi for the dielectric constant in the different regions of the proposed TFET biosensor. To obtain the general solution of Equation (1), the effect of mobile charges is neglected and the equation is presented as Equation (2) below. $${\psi }_i\left(x,y\right)=E_{1i}\left(x\right)+E_{2i}\left(x\right)y+E_{3i}\left(x\right)y^2$$

$$E_{2i}\left(x\right)={\eta }_i\left({\psi }_{s,i}\left(x\right)-{\psi }_{G,i}\right)$$

$$E_{3i}\left(x\right)=-{\eta }_i\frac{\left({\psi }_{s,i}\left(x\right)-{\psi }_{G,i}\right)}{t_{si}}$$

In equation (2), E1i(x), E2i(x), and E3i(x) denote the coefficients in the nine different regions. These coefficients can be obtained by using the constraints, the coefficients using the constraints are given as equations (3), (4) and (5) below. $$E_{1i}\left(x\right)={\psi }_{s,i}\left(x\right)$$

$$E_{2i}\left(x\right)=n_i\left({\psi }_{s,i}\left(x\right)-{\psi }_{G,i}\right)$$

$$E_{3i}\left(x\right)=-n_i\frac{\left({\psi }_{s,i}\left(x\right)-{\psi }_{G,i}\right)}{t_{si}}$$

The 1-D equation resulting from solving equations (1) and (2) using the coefficients is presented in equation (6). $$\frac{{\partial }^2{\psi }_{s,i}\left(x\right)}{\partial x^2}-k_i^2{\psi }_{s,i}\left(x\right)-a_i=0$$

$${\alpha }_i=\left(-q{N}_i/{\epsilon }_{Ge}\right)-\left(2{\eta }_i/t_{Ge}\right){\psi }_{G,i}{}_{{}_{;\text{i}=\mathrm{1,2,3}}}$$

$${\alpha }_i=\left(-q{N}_i/{\epsilon }_{Si}\right)-\left(2{\eta }_i/t_{Ge}\right){\psi }_{G,i}{}_{{}_{;\text{i}=\mathrm{4,5,6,7,8,9}}}$$

Where in equation (6) $$k_i^2={\left(2n_i/t_{Si}\right)}_{;\text{i}=\mathrm{1,2....,9}}$$

$$a_i=\left(-q{N}_i/e_{Ge}\right)-\left(2n_i/t_{Ge}\right){\psi }_{G,i}{}_{{}_{;\text{i}=\mathrm{1,2,3}}}$$

$$a_i=\left(-q{N}_i/e_{Si}\right)-\left(2n_i/t_{Ge}\right){\psi }_{G,i}{}_{{}_{;\text{i}=\mathrm{4,5,6,7,8,9}}}$$

The solution to Equation (6) can be given by Equation (7) below, which represents the surface potential in all nine regions. $${\psi }_{s,i}\left(x\right)=A_i{e}^{k_{i}x}+B_i{e}^{-k_{i}x}-{\frac{a_i}{k_i^2}}_{{}_{;\text{i}=1.2...\mathrm{,9}}}$$

The coefficient of Equation (7) can be found by using and solving the fact that the electric field and potential are continuous at the boundaries of each region.

$$V_{bip}=-\frac{KT}{q}\text{ln}\left(\frac{N_a}{n_{i,Ge}}\right)$$

$${\psi }_{s9}\left(x=L_1+L_2+L_3+L_4+L_5+L_6+L_7+L_8+L_9\right)=V_{bin}+V_{ds}$$

$$V_{bin}=-\frac{KT}{q}\text{ln}\left(\frac{N_d{N}_{cn}}{n_{i,Si}^2}\right)$$

The potentials at the source-channel and at the channel-drain junctions are given in equations (8), (9), (10) and (11): $${\psi }_{s1}\left(x=0\right)=V_{bip}$$

$$V_{bip}=-\frac{KT}{q}\text{ln}\left(\frac{N_a}{n_{i,Ge}}\right)$$

$${\psi }_{s9}\left(x=L_1+L_2+L_3+L_4+L_5+L_6+L_7+L_{\mathrm{8th}}+L_9\right)=V_{bin}+V_{\mathrm{i.e}s}$$

$$V_{bin}=-\frac{KT}{q}\text{ln}\left(\frac{N_{\mathrm{i.e}}{N}_{cn}}{n_{i,Si}^2}\right)$$

$${\frac{\partial {\psi }_{s,i}\left(x\right)}{\partial x}|}_{x={\displaystyle \sum _{j=1}^i{L}_j}}={\frac{{\psi }_{s,\left(i+1\right)}\left(x\right)}{\partial x}|}_{x={{\displaystyle \sum _{j=1}^i{L}_j}}_{{}_{;\text{i}=\mathrm{1,2....,8}}}}$$

The remaining continuity criteria are given in equations (12) and (13). $${{\psi }_{s,i}\left(x\right)|}_{x={\displaystyle \sum _{j=1}^i{L}_j}}={{\psi }_{s,\left(i+1\right)}\left(x\right)|}_{x={{\displaystyle \sum _{j=1}^i{L}_j}}_{{}_{;\text{i}=\mathrm{1,2....,8}}}}$$

$${\frac{\partial {\psi }_{s,i}\left(x\right)}{\partial x}|}_{x={\displaystyle \sum _{j=1}^i{L}_j}}={\frac{{\psi }_{s,\left(i+1\right)}\left(x\right)}{\partial x}|}_{x={{\displaystyle \sum _{j=1}^i{L}_j}}_{{}_{;\text{i}=\mathrm{1,2....,8}}}}$$

$$X={\left[\begin{array}{cccccccccccccccccc}{A}_1& B_1& A_2& B_2& A_3& B_3& A_4& B_4& A_5& B_5& A_6& B_6& A_7& B_7& A_8& B_8& A_9& B_9\end{array}\right]}^T$$

$$M={\left[\begin{array}{cccccccccccccccccc}{M}_1& M_2& 0& M_3& 0& M_4& 0& M_5& 0& M_6& 0& M_7& 0& M_8& 0& M_9& 0& M_{10}\end{array}\right]}^T$$

Applying boundary conditions to equation (4) leads to fourteen simultaneous equations, where the equations are explained in terms of a matrix as shown below, where LX = M. $$L=\left[\begin{array}{cccccccccccccccccc}1& 1& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& & \\ a_1& b_1& -c_1& -{\mathrm{i.e}}_1& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& & \\ {\lambda }_1{a}_1& -{\lambda }_1{b}_1& -{\lambda }_2{c}_1& {\lambda }_2{\mathrm{i.e}}_1& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& & \\ 0& 0& a_2& b_2& -c_2& -{\mathrm{i.e}}_2& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& & \\ 0& 0& {\lambda }_2{a}_2& -{\lambda }_2{b}_2& -{\lambda }_3{c}_2& {\lambda }_3{\mathrm{i.e}}_2& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& a_3& b_3& -c_3& -{\mathrm{i.e}}_3& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& {\lambda }_3{a}_3& -{\lambda }_{30}{b}_3& -{\lambda }_4{c}_3& {\lambda }_4{\mathrm{i.e}}_3& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& a_4& b_4& -c_4& -{\mathrm{i.e}}_4& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& {\lambda }_4{a}_4& -{\lambda }_4{b}_4& -{\lambda }_5{c}_4& {\lambda }_5{\mathrm{i.e}}_4& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& a_5& b_5& -c_5& -{\mathrm{i.e}}_5& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& {\lambda }_5{a}_5& -{\lambda }_5{b}_5& -{\lambda }_6{c}_5& {\lambda }_6{\mathrm{i.e}}_5& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& a_6& b_6& -c_6& -{\mathrm{i.e}}_6& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& {\lambda }_6{a}_6& -{\lambda }_6{b}_6& -{\lambda }_7{c}_6& {\lambda }_7{\mathrm{i.e}}_6& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& a_6& b_7& -c_7& -{\mathrm{i.e}}_7& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& {\lambda }_7{a}_7& -{\lambda }_7{b}_7& -{\lambda }_{\mathrm{8th}}{c}_7& {\lambda }_{\mathrm{8th}}{\mathrm{i.e}}_7& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& a_{\mathrm{8th}}& b_{\mathrm{8th}}& -c_{\mathrm{8th}}& -{\mathrm{i.e}}_7\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& {\lambda }_{\mathrm{8th}}{a}_{\mathrm{8th}}& -{\lambda }_{\mathrm{8th}}{b}_{\mathrm{8th}}& -{\lambda }_9{c}_{\mathrm{8th}}& {\lambda }_9{\mathrm{i.e}}_{\mathrm{8th}}\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0& a_9& b_9\end{array}\right]$$

$$X={\left[\begin{array}{cccccccccccccccccc}{A}_1& B_1& A_2& B_2& A_3& B_3& A_4& B_4& A_5& B_5& A_6& B_6& A_7& B_7& A_{\mathrm{8th}}& B_{\mathrm{8th}}& A_9& B_9\end{array}\right]}^T$$

$$M={\left[\begin{array}{cccccccccccccccccc}{M}_1& M_2& 0& M_3& 0& M_4& 0& M_5& 0& M_6& 0& M_7& 0& M_{\mathrm{8th}}& 0& M_9& 0& M_{10}\end{array}\right]}^T$$

$$M_1=V_{bip}+\left({\alpha }_1/k_1^2\right),M_{10}=V_{bin}+V_{ds}+\left({\alpha }_9/k_9^2\right),$$

$$a_j=e^{{\lambda }_j{\displaystyle \sum _1^j{L}_j}},b_j=e^{-{\lambda }_j{\displaystyle \sum _1^j{L}_j}};j=\mathrm{1,}\mathrm{2...,}9$$

$$c_p=e^{{\lambda }_{p+1}{\displaystyle \sum _1^p{L}_i}},{\text{d}}_p=e^{-{\lambda }_{p+1}{\displaystyle \sum _1^p{L}_i}};\text{p}=\mathrm{1,2}\dots \mathrm{,8.}$$

Where in the above matrix the A, X and C are represented where, $$M_j=\left(a_{j-1}/k_{j-1}^2\right)-\left(a_j/k_j^2\right);\text{j}=2\text{to}\mathrm{9,}$$

$$M_1=V_{bip}+\left(a_1/k_1^2\right),M_{10}=V_{bin}+V_{\mathrm{i.e}s}+\left(a_9/k_9^2\right),$$

$$a_j=e^{{\lambda }_j{\displaystyle \sum _1^j{L}_j}},b_j=e^{-{\lambda }_j{\displaystyle \sum _1^j{L}_j}};j=\mathrm{1,}\mathrm{2...,}9$$

$$c_p=e^{{\lambda }_{p+1}{\displaystyle \sum _1^p{L}_i}},{\text{i.e}}_p=e^{-{\lambda }_{p+1}{\displaystyle \sum _1^p{L}_i}};\text{p}=1.2...\mathrm{,8th.}$$

Similarly, the surface potential for the lower gate at y=0 can be derived using the same procedure except that deriving the surface potential for the lower gate skips the calculation for region 8.

The expression for the width of the depletion zone

$$L_d=\sqrt{\frac{2{\epsilon }_{Si}}{q}\left(\frac{1}{N_a}+\frac{1}{N_d}\right)\left\{\frac{KT}{q}\text{ln}\left(\frac{N_a{N}_d}{n_{i,Si}^2}\right)+V_{ds}\right\}}$$

The iterative methods can be used for the calculation of the source-channel and channel-drain junction depletion width, but the calculation is done using an approximation method and the source-channel and channel-drain junction depletion width is given in equation ( 14) and (15) indicated. $$L_s=\sqrt{\frac{2e_{Si}{e}_{Ge}{\left(N_{\mathrm{i.e}}+N_a\right)}^2}{q{N}_a{N}_{\mathrm{i.e}}\left(e_{Si}{N}_{\mathrm{i.e}}+e_{Ge}{N}_a\right)}\frac{KT}{q}\text{ln}\left(\frac{N_a{N}_{\mathrm{i.e}}}{n_{i,Ge}{n}_{i,Si}}\right)}$$

$$L_{\mathrm{i.e}}=\sqrt{\frac{2e_{Si}}{q}\left(\frac{1}{N_a}+\frac{1}{N_{\mathrm{i.e}}}\right)\left\{\frac{KT}{q}\text{ln}\left(\frac{N_a{N}_{\mathrm{i.e}}}{n_{i,Si}^2}\right)+V_{\mathrm{i.e}s}\right\}}$$

The expression for the electric field

$$E_Y=E_{Y,i}=-{\frac{\partial {\psi }_{s,i}\left(x,y\right)}{\partial y}|}_{x=\text{constant}}$$

The surface potential can be used to determine the X and Y components of the electric field, where the relationship between the electric field and the potential is given by equations (16) and (17). $$E_X=E_{X,i}=-{\frac{\partial {\psi }_{s,i}\left(x\right)}{\partial x}|}_{y=t_{Si}\text{or}y=0}$$

$$E_Y=E_{Y,i}=-{\frac{\partial {\psi }_{s,i}\left(x,y\right)}{\partial y}|}_{x=\text{constant}}$$

$$E_y=-\left(E_{2i}\left(x\right)-2y{E}_{3i}\left(x\right)\right)$$

The X and Y components of the electric field are represented by equations (18) and (19) below. $$E_x=-\left(k_i{A}_i{e}^{k_{i}x}-k_i{B}_i{e}^{-k_{i}x}\right)$$

$$E_y=-\left(E_{2i}\left(x\right)-2y{E}_{3i}\left(x\right)\right)$$

The expression for the drain current

The drain current is modeled using the Kane model, where the drain current is calculated by integrating the generation rate (G) of carriers throughout the device structure, and hence the drain current is given by equation (20). $$I_{DS}=q{\displaystyle {\int }_{vOl}{G}_{BTBT}\mathrm{i.e}v}$$

The tunnel generation rate is given by equation (21). $$G_{BTBT}\left(E\right)=A{E}^a\text{ex}\left(-\frac{B}{E}\right)$$

$$B=\frac{{\pi }^2{E}_g^{\frac{3}{2}}\sqrt{\frac{m_{tunnel}}{2}}}{qh}$$

In Equation (21), A and B are the standard Kane parameters which depend on the effective mass of the electron and are expressed in Equations (22) and (23). $$A=\frac{q^2\sqrt{2m_{t\mathrm{and}nnel}}}{H^2\sqrt{E_G}}$$

$$B=\frac{{\pi }^2{E}_G^{\frac{3}{2}}\sqrt{\frac{m_{t\mathrm{and}nnel}}{2}}}{qH}$$

In equation (21), the coefficient α = 2 and 2.5 for direct and indirect BTBT, respectively. In the proposed biosensing device, the BTBT is located in the region of the source pocket located in the Si _0.8 Ge _0.2 . Therefore, the parameters A and B of the Si _0.8 Ge _0.2 are taken into account for the calculation of the drain current given by equation (24) below. $$I_{DS}=q{\displaystyle \iint A{E}_{avG}^a\text{ex}\left(-B/E_{avG}\right)\mathrm{i.e}v}$$

Equation (25) below is used to calculate the average electric field (Eavg). $$E_{avG}=\left({\displaystyle {\int }_{L_{BW}}{E}_{TOtal}\mathrm{i.e}y}\right)/L_{BW}$$

und Ex und Ey werden während der Berechnung für den Ausdruck des elektrischen Feldes berechnet.In equation (25), L _BW denotes the barrier width calculated at the point where the electric field is maximum and the local electric field is, $E_{TOtal}={\left(E_x^2+E_y^2\right)}^{1/2}$

and Ex and Ey are calculated during the calculation for the electric field term.

The final expression for the drain current can be represented as equation (26). $$I_D=q{t}_{si}{L}_{BW}{G}_{BTBT}\left(E_{avG}\right)$$

The above expressions for surface potential, depletion region width, electric field and drain current represent the developed analytical model of the proposed biosensor, and the results obtained for the analytical model are compared with the results of the simulation of the proposed biosensor.

In one embodiment, insulators are used in the nanogaps to use only one type of cancer cells in the nanogaps at a time, the insulators having a dielectric constant corresponding to the cancer cells. In the structure of the proposed device, the gate has been removed above the drain-channel junction region, so there is no BTBT in this region when the negative gate voltage is applied, resulting in a reduction in the ambipolar current in the off-state and in the ambipolar state. In the region where band-to-band tunneling occurs in the region of the source-channel junction, the charge carriers tunnel from the valance band of the source to the conduction band of the drain when all four nanogaps are filled with neutral cancer cells with a dielectric constant of K = 32 are filled. BTBT area increases because germanium has a narrower bandgap compared to silicon, resulting in an increase in the number of carriers tunneling from the source valance band to the pocket conduction band, resulting in increased inrush current.

In one embodiment, the effects of temperature on the transmission properties are studied when the nanogaps are completely filled with healthy and neutral cancer cells with different dielectric constants at different temperatures to study the thermal stability of the proposed biosensor device. The results of the study showed that the leakage current increases as the temperature increases above 300 K, but the device is still able to detect the cancer cells present in the biosensor's nanogaps. It is also shown that the proposed biosensor improves the conditions for SS by using lower bandgap material at the source, resulting in an increase in on-current and a reduction in threshold voltage. The threshold voltage is calculated using the constant current approach, where the threshold voltage is the gate voltage at which the drain current reaches 10 ^-7 A.

In one embodiment, there is a high E-field in the source-channel junction region during the on-state due to the use of a thin, high-dielectric-constant material used as the gate oxide, and thereby an increase in BTBT tunneling in the source channel area, eventually leading to an increase in on-state drain current.

In one embodiment, the fill factor of the embedded nanogap is defined as the percentage of the total area of the nanogap that is filled by immobilized cancer cells. The sensitivity of the proposed biosensor is the parameter that identifies the change in the electrical parameters of the device as the cancer cells in the nanogap change. A device with higher sensitivity is preferably used for the detection of cancer cells located in the nanoholes. The sensitivity of the proposed biosensor can be defined in terms of the drain current according to equation (27) below. $$\text{sensitivity},S_n={\text{I}}_{\mathrm{i.e}s,K\mathrm{right}ebs}-{\text{I}}_{\mathrm{i.e}s,Ges\mathrm{and}n\mathrm{i.e}}/{\text{I}}_{\mathrm{i.e}s,Ges\mathrm{and}n\mathrm{i.e}}$$

In the equation, Ids, cancer and Ids, healthy denote the drain current of the biosensor when the nanogaps are filled with cancer cells and healthy cells. The sensitivity of the proposed biosensor increases with the increase in the dielectric constant of the cancer cells, and the sensitivity also increases with the increase in the fill factor of the nanogaps present in the device.

In one embodiment, the effects of the immobile positively and negatively charged cancer cells in the nanogaps of the proposed TFET-based biosensor on drain current and threshold voltage are investigated. It shows that the drain current increases and the threshold span Voltage decreases when the cancer cell charge changes from negative to positive because less gate voltage is needed to achieve a drain current of ^10-7 A. This is due to the charge present on the cancer cells in the gate electric field. As the negative change on the cancer cells increases from 5x10 ¹⁷ C/cm ² to 1x10 ¹⁹ C/cm ² the threshold voltage of the device for the different cancer cells with different dielectric constants increases. It is observed that the threshold voltage of the biosensor for cancer cells with different dielectric constant decreases as the positive charge increases from 1×10 ¹⁸ C/cm ² to 6×10 ¹⁸ C/cm ² .

In one embodiment, the effects of the charged cancer cells on the drain current sensitivity are studied, where as the negative change increases from 1×10 ¹⁸ C/cm ² to 6×10 ¹⁸ C/cm ² on the immobilized cancer cell with varying dielectric constants, the The sensitivity of the device decreases, the sensitivity of the device decreases, but with the increase in the positive change on the cancer cells from 1×10 ¹⁸ C/cm ² to 6×10 ¹⁸ C/cm ² the sensitivity of the device increases, because the positive charges, present on the cancer cell contribute to the electric field at the source-channel junction and this leads to an increase in BTBT at the source-channel junction.

The figures and the preceding description give examples of embodiments. Those skilled in the art will understand that one or more of the elements described may well be combined into a single functional element. Alternatively, certain elements can be broken down into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of the processes described herein may be changed and is not limited to the manner described herein. Additionally, the actions of a flowchart need not be performed in the order shown; Also, not all actions have to be carried out. Also, those actions that are not dependent on other actions can be performed in parallel with the other actions. The scope of the embodiments is in no way limited by these specific examples. Numerous variations are possible, regardless of whether they are explicitly mentioned in the description or not, e.g. B. Differences in structure, dimensions and use of materials. The scope of the embodiments is at least as broad as indicated in the following claims.

Advantages, other benefits, and solutions to problems have been described above with respect to particular embodiments. However, the benefits, advantages, problem solutions, and components that can cause an advantage, benefit, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or component of any or all claims.

Reference List

100

A novel device for detecting breast cancer cells with two Si _0.8 Ge _0.2 gates.

102

swelling layer

104

Pocket Layer

106

channel layer

108

drain layer

110

A multitude of HfO ₂ layers

112

A variety of SiO2 layers

114

Multiple gate metals

116

tunnel gate

118

auxiliary gate

202

gate metal M1

204

Gate metal M2

206

breast cancer cells

208

healthy cells

Claims (10)

A novel dual gate Si _0.8 Ge _0.2 breast cancer cell line detection device, the device comprising: a source layer having a length of 17 nm doped with the arsenic dopant at a concentration of 1.5 x 10 ²⁰ ; a pocket layer 5 nm long doped with the boron dopant at a concentration of 2×10 ¹⁹ , a channel layer 13 nm long doped with the arsenic dopant at a concentration 2×10 ¹⁴ , a drain layer with a length of 25 nm doped with the boron dopant at a concentration of 3×10 ¹⁷ ; a plurality of HfO ₂ layers 1 nm thick and 22 nm long used as gate oxide on the top and bottom of the device; a plurality of SiO ₂ layers with a width of 2 nm and a height of 5 nm arranged over the HfO ₂ layer; and a plurality of gate metals disposed over the SiO ₂ layer on both top and bottom surfaces, with nanovoids in the device each having a width of 5 nm. system after claim 1 , wherein the device consists of 20 nm Si _0.8 Ge _0.2 and 50 nm silicon, the thickness of Si and Ge being 10 nm. system after claim 1 , where a tunnel gate consisting of gate metal (M1) with a work function of 3.75eV is formed at the top and bottom of the device and the length of this tunnel gate is 11 nm, the top and bottom tunnel gate nanogaps have a length of 10 nm to have. system after claim 1 , wherein an auxiliary gate at the top of the device consists of gate metal (M2) having a work function of 5.0 eV and the auxiliary gate has a length of 6 nm, wherein the nanogap of the auxiliary gate has a length of 5 nm. system after claim 1 , where an area of the total nanogap area for the cancer cells is 100 nm ² in case of tunnel gate nanogap and 25 nm ² in case of auxiliary gate nanogap. system after claim 1 , wherein the gate oxide, which is the HfO ₂ layer, extends from the drain layer side so that it can act as a spacer to increase the electric field toward the center of the device. system after claim 1 , using the SiO ₂ layer to support the gate metal due to its low dielectric constant compared to HfO ₂ , making the developed device more sensitive to the dielectric constant of the cancer cells and thus having less effect of the oxide support on the inrush current. system after claim 1 , whereby an analytical model of the proposed device is developed, in which the effects of the charge present on the cancer cells on the electrical parameters of the device are studied in detail, and then the analytical results are compared and verified with the results obtained by performing the Simulation of the proposed device can be obtained. system after claim 1 , examining the sensitivity of the proposed device to various neutral cancer cells and non-tumorigenic healthy cells, and then studying the effects of the negatively and positively charged cells on the sensitivity and threshold voltage of the proposed device. system after claim 1 , where a thermal stability study is performed on the proposed device by varying the temperature from 215 K to 400 K.

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