中国物理B ›› 2026, Vol. 35 ›› Issue (2): 28703-028703.doi: 10.1088/1674-1056/adecfa

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Performance analysis of an in-built N+ pocket electrically doped TFET biosensor for biomedical applications

Chan Shan(单婵)1, Qian-nan Wang(王倩楠)1, and Ying Liu(刘赢)2,3,†   

  1. 1 School of Ocean Information Engineering, Jimei University, Xiamen 361021, China;
    2 Faculty of Data Science and Information Technology, INTI International University, Negeri Sembilan, 71800, Malaysia;
    3 School of Software, Quanzhou University of Information Engineering, Quanzhou 362008, China
  • 收稿日期:2025-04-30 修回日期:2025-06-12 接受日期:2025-07-08 发布日期:2026-01-31
  • 通讯作者: Ying Liu E-mail:liuying@foxmail.com
  • 基金资助:
    Project supported by the Ministry of Education’s Supply and Demand Matching Employment and Education Project (Grant No. 2024110776329).

Performance analysis of an in-built N+ pocket electrically doped TFET biosensor for biomedical applications

Chan Shan(单婵)1, Qian-nan Wang(王倩楠)1, and Ying Liu(刘赢)2,3,†   

  1. 1 School of Ocean Information Engineering, Jimei University, Xiamen 361021, China;
    2 Faculty of Data Science and Information Technology, INTI International University, Negeri Sembilan, 71800, Malaysia;
    3 School of Software, Quanzhou University of Information Engineering, Quanzhou 362008, China
  • Received:2025-04-30 Revised:2025-06-12 Accepted:2025-07-08 Published:2026-01-31
  • Contact: Ying Liu E-mail:liuying@foxmail.com
  • Supported by:
    Project supported by the Ministry of Education’s Supply and Demand Matching Employment and Education Project (Grant No. 2024110776329).

摘要: An in-built N$^{+}$ pocket electrically doped tunnel field-effect transistor (ED-TFET)-based biosensor has been reported for the first time. The proposed device begins with a PN junction structure with a control gate (CG) and two polarity gates (PG1 and PG2). Utilizing the polarity bias concept, a narrow N$^{+}$ pocket is formed between the source and channel without the need for additional doping steps, achieved through biasing PG1 and PG2 at $-1.2 $ V and 1.2 V, respectively. This method not only addresses issues related to doping control but also eliminates constraints associated with thermal budgets and simplifies the fabrication process compared to traditional TFETs. To facilitate biomolecule sensing within the device, a nanogap cavity is formed in the gate dielectric by selectively etching a section of the polarity gate dielectric layer toward the source side. The investigation into the presence of neutral and charged molecules within the cavities has been conducted by examining variations in the electrical properties of the proposed biosensor. Key characteristics assessed include drain current, energy band, and electric field distribution. The performance of the biosensor is measured using various metrics such as drain current ($I_{\rm DS}$), subthreshold swing (SS), threshold voltage ($V_{\rm TH}$), drain current ratio ($I_{\rm ON}/I_{\rm OFF}$). The proposed in-built N$^{+}$ pocket ED-TFET-based biosensor reaches a peak sensitivity of 1.08$\times10^{13}$ for a neutral biomolecule in a completely filled nanogap with a dielectric constant of 12. Additionally, the effects of cavity geometry and different fill factors (FFs) on sensitivity are studied.

关键词: electrically doped, label-free biosensors, PNPN tunnel field-effect transistors (TFETs), sensitivity

Abstract: An in-built N$^{+}$ pocket electrically doped tunnel field-effect transistor (ED-TFET)-based biosensor has been reported for the first time. The proposed device begins with a PN junction structure with a control gate (CG) and two polarity gates (PG1 and PG2). Utilizing the polarity bias concept, a narrow N$^{+}$ pocket is formed between the source and channel without the need for additional doping steps, achieved through biasing PG1 and PG2 at $-1.2 $ V and 1.2 V, respectively. This method not only addresses issues related to doping control but also eliminates constraints associated with thermal budgets and simplifies the fabrication process compared to traditional TFETs. To facilitate biomolecule sensing within the device, a nanogap cavity is formed in the gate dielectric by selectively etching a section of the polarity gate dielectric layer toward the source side. The investigation into the presence of neutral and charged molecules within the cavities has been conducted by examining variations in the electrical properties of the proposed biosensor. Key characteristics assessed include drain current, energy band, and electric field distribution. The performance of the biosensor is measured using various metrics such as drain current ($I_{\rm DS}$), subthreshold swing (SS), threshold voltage ($V_{\rm TH}$), drain current ratio ($I_{\rm ON}/I_{\rm OFF}$). The proposed in-built N$^{+}$ pocket ED-TFET-based biosensor reaches a peak sensitivity of 1.08$\times10^{13}$ for a neutral biomolecule in a completely filled nanogap with a dielectric constant of 12. Additionally, the effects of cavity geometry and different fill factors (FFs) on sensitivity are studied.

Key words: electrically doped, label-free biosensors, PNPN tunnel field-effect transistors (TFETs), sensitivity

中图分类号:  (Biosensors)

  • 87.85.fk
85.30.Tv (Field effect devices) 85.30.De (Semiconductor-device characterization, design, and modeling) 85.30.Mn (Junction breakdown and tunneling devices (including resonance tunneling devices))