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KR-20260064739-A - Junction field-effect transistor and related manufacturing method

KR20260064739AKR 20260064739 AKR20260064739 AKR 20260064739AKR-20260064739-A

Abstract

The present invention relates primarily to a junction field-effect transistor (FET) (1), or “SiC JFET,” made entirely of SiC. It is preferably manufactured according to a top-down approach, and its manufacturing is suitable for mass production. The electrical performance of the proposed SiC JFET (1) was evaluated in a dry state and in a liquid medium. A proof of concept for using the proposed SiC JFET as a biosensor (0) was verified by pH measurements. The proposed SiC JFET achieves a sensitivity of up to 495 mV/pH, which is nearly 100 times greater than the theoretical Nernst limit. Therefore, since it meets the performance generally required in this field, such as sensitivity and chemical stability, particularly over long periods, it has a suitable application for various in vitro and in vivo biochemical detection applications.

Inventors

  • 카르커 올파
  • 스탐불 발레리
  • 바노 에드윗즈
  • 제켄테스 콘스탄티노스

Assignees

  • 엥스띠뛰 뽈리떼끄니끄 드 그르노블
  • 유니베르시떼 그르노블 알프스
  • 상뜨로 나쇼날 드 라 러쉐르쉐 샹띠피크
  • 위니베르시테 사부와 몽 블랑

Dates

Publication Date
20260507
Application Date
20240909
Priority Date
20230912

Claims (8)

  1. An ion-sensitive biosensor (0) comprising at least one analyte (4) receiving region, wherein the ion-sensitive biosensor (0) comprises at least one junction field-effect transistor (1), and each junction field-effect transistor (1) is: A substrate (11) containing silicon carbide (SiC) and having a first type of doping, On the substrate (11), a first crystal layer (12) comprising SiC and having a second type of doping different from the first type, On the first portion (121) of the first crystal layer (12): i. At least one crystal channel (13) containing SiC and having the first type of doping, ii. On the first end (131) of each crystal channel (13), a source ohmic contact (14) comprising SiC and having the first type of doping, and iii. On the second end (132) of each crystal channel (13), a drain ohmic contact portion (15) comprising SiC and having the first type of doping, On the second portion (122) of the first crystal layer (12) adjacent to the first portion (121), at least two pads (16, 17) for forming ohmic contacts, Between each source ohmic contact portion (14) and at least one first pad (16) of at least two pads (16, 17) for forming the ohmic contact, at least one first conductive track (18) extending on the first crystal layer (12), and Between each drain ohmic contact portion (15) and at least one second pad (17) different from at least one first pad (16) among the at least two pads (16, 17) for forming the ohmic contact, at least one second conductive track (19) extending on the first crystal layer (12), Includes, Thus, each receiving region of the ion-sensitive biosensor (0) is located on the exposed surface of at least one, preferably a crystal channel (13) of each junction field-effect transistor (1).
  2. In paragraph 1, An ion-sensitive biosensor (0) further comprising a wall (31) preferably comprising PDMS, which forms a receiving portion for an analyte (4) between the ends of each determination channel or a plurality of determination channels (13).
  3. In paragraph 1, An ion-sensitive biosensor (0) further comprising walls preferably comprising PDMS, forming a fluid circulation channel (32) for an analyte (4) between the ends (131, 132) of each determination channel or a plurality of determination channels (13).
  4. In any one of paragraphs 1 through 3, An ion-sensitive biosensor (0) further comprising a reference electrode (2) intended to be at least partially immersed in an analyte (4).
  5. A method for manufacturing an ion-sensitive biosensor (0) comprising at least one analyte (4) receiving region, wherein the method comprises the following steps: Step of providing a laminate (10) including the following: i. A substrate (11) comprising silicon carbide (SiC) and having a first type of doping, ii. On the substrate (11), a first crystal layer (12) comprising SiC and having a second type of doping different from the first type, iii. On the first crystal layer (12), a second crystal layer (130) comprising SiC and having the first type of doping, and iv. On the second crystal layer (130), a third crystal layer (140) comprising SiC and having the first type of doping, Step of depositing a first electrically conductive layer on the third crystal layer (140), The step of etching the third crystal layer (140) through the first electrically conductive layer acting as an etching mask to expose a portion of the second crystal layer (130) and forming at least one source ohmic contact (14) and a drain ohmic contact (15), and Step of etching the above first electrically conductive layer to form the following: i. At least two pads (16, 17) for forming ohmic contact, ii. between each source ohmic contact portion (14) and at least one first pad (16) of at least two pads (16, 17) for forming the ohmic contact, at least one first conductive track (18) extending on the first crystal layer (12), and iii. between each drain ohmic contact portion (15) and at least one second pad (17) different from at least one first pad (16) among at least two pads (16, 17) for forming the ohmic contact, at least one second conductive track (19) extending on the first crystal layer (12), A step of etching an exposed portion of the second crystal layer (130) to form at least one crystal channel (13), The method includes manufacturing a junction field-effect transistor (1) along the way, Thus, each receiving region of the ion-sensitive biosensor (0) is located on at least one, preferably on the exposed surface of the crystal channel (13) of each junction field-effect transistor (1). Manufacturing method.
  6. In paragraph 5, A manufacturing method in which the exposed portion of the second crystal layer (130) is etched to form a plurality of parallel crystal channels (13) separated from each other.
  7. In paragraph 5 or 6, Step of depositing a passivation layer (33) on at least a portion of the outer circumference of the etched exposed portion of the second crystal layer (130). A manufacturing method further comprising
  8. An application for measuring the hydrogen ion concentration (hydrogen potential) (pH) of an analyte (4) using an ion-sensitive biosensor (0) according to any one of claims 1 to 4, particularly in vivo in a biological environment or in vitro in an environment where the pH is less than 3 or greater than 8.

Description

Junction field-effect transistor and related manufacturing method The present invention relates to the field of biosensors. The present invention is particularly advantageously used in the field of diagnosis. Silicon (Si)-based field-effect transistors have been intensively developed in recent years and have proven highly promising for biochemical detection applications based on label-free, real-time, selective, and high-sensitivity electrical measurements. However, the low biocompatibility and limited chemical inertness of Si are major barriers to the development and commercialization of FET-based biosensors for long-term in vitro and in vivo applications. More specifically, the limited reliability of field-effect transistors containing Si hinders the use of such devices for organ detection, particularly when the detection environment is “harsh,” namely the human body. None of the forms of Si (nanowires, bulk forms, etc.) meet the required reliability conditions because the material possesses both a lack of organ chemical stability and a lack of biocompatibility, especially when deployed in physiological environments. While these drawbacks of Si-based biosensors may be acceptable when the biosensors are intended for single-use detection, they are unacceptable for organ detection, such as in vitro and in vivo detection. For example, significant effort has been devoted to the development of silicon-based hydrogen ion concentration (pH) sensors for continuous in vivo monitoring. Consequently, ion-sensitive field-effect transistors containing Si have been developed, but they still fail to meet the criteria required for intended applications. Therefore, it has now become absolutely necessary to replace Si with other materials, optionally semiconductors, that provide intrinsic chemical robustness, electrical properties similar to Si, and satisfactory biocompatibility. In this regard, silicon carbide (SiC) appears to be a viable alternative material due to the combination of excellent mechanical, electrical, and chemical properties with biocompatibility. Indeed, SiC has been shown to possess higher chemical inertness than Si when immersed in physiological solutions, as well as higher biocompatibility. Furthermore, the use of SiC offers the advantage of compatibility with Si microfabrication technologies. Therefore, SiC is expected to replace Si in the development of biosensors due to its superior properties compared to Si, particularly for multi-use applications or long-term applications. Awais et al. have already taken an interest in this promising material and investigated the effect of pH on the transport characteristics of field-effect transistors containing SiC nanowires (cf. M. Awais, Habeeb Mousa, K. Teker, Effect of pH on transport characteristics of silicon carbide nanowire field-effect transistor (SiCNW-FET), Journal of Materials Science: Materials in Electronics, 32 (2021) 3431-3436). This literature reports the fabrication of a FET containing SiC nanowires transferred onto a silicon-on-insulator (SOI) substrate for pH measurement. The proposed fabrication method follows a bottom-up approach because the SiC nanowires are connected after being transferred. This causes a problem of non-reproducibility of signals between nanowires because the nanowires are never completely identical and are not connected in the same way. In addition, it is desirable to propose a method for manufacturing a silicon-containing FET that can be implemented in a uniform manner at the wafer scale. This will contribute to reducing the risk of signal non-reproducibility. The object, goal, as well as the features and advantages of the present invention, will become more apparent from the detailed description of one embodiment of the present invention illustrated by the following accompanying drawings: FIG. 1 schematically illustrates a partial cross-sectional view of a field-effect transistor and a biosensor including the field-effect transistor according to an embodiment of the first aspect of the present invention. FIGS. 2a and 2b are drawings illustrating protonation and deprotonation phenomena observable in the electric double layer or EDL of a field-effect transistor according to an embodiment of the first aspect of the present invention, depending on whether the analyte under consideration has a low pH (Fig. 2a), e.g., less than 3, or a high pH (Fig. 2b), e.g., greater than 8. FIG. 3 graphs the shift in the current-voltage transfer characteristics of a buffer solution in a crystal channel having n-type doping of a field-effect transistor according to an embodiment of the first aspect of the present invention. FIG. 4 schematically illustrates a cross-sectional view of a field-effect transistor according to another embodiment of the first aspect of the present invention compared with that shown in FIG. 1. FIG. 5 schematically illustrates a perspective view of a field-effect transistor according to another embodiment of the firs