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CN-121985996-A - Junction field effect transistor and related manufacturing method

CN121985996ACN 121985996 ACN121985996 ACN 121985996ACN-121985996-A

Abstract

The invention first includes a Junction Field Effect Transistor (JFET), i.e., a "SiC JFET", made entirely of SiC. The transistor is preferably manufactured in a top-down process, which is suitable for mass production. The electrical properties of the proposed SiC JFET have been evaluated in dry conditions and in liquid media. The conceptual feasibility of the proposed SiC JFET as a biosensor 0 was verified by pH measurement. The sensitivity of the proposed SiC JFET is as high as 495 mV/ph, i.e. nearly 100 times higher than the theoretical nernst limit. Thus, the device is suitable for a variety of in vitro and in vivo biochemical detection applications, as the device meets performance criteria commonly required in the field, such as sensitivity and chemical stability, particularly long-term stability.

Inventors

  • Orfa Cocer
  • Valerie Stambuli
  • Edvig Barnes&Noble
  • Constantinos Zekentes

Assignees

  • 格勒诺布尔理工学院
  • 格勒诺布尔-阿尔卑斯大学
  • 国家科学研究中心
  • 萨瓦勃朗峰大学

Dates

Publication Date
20260505
Application Date
20240909
Priority Date
20230912

Claims (8)

  1. 1. Ion-sensitive biosensor (0) characterized by comprising at least one analyte (4) receiving area, the ion-sensitive biosensor (0) comprising at least one junction field effect transistor (1), each junction field effect transistor (1) comprising: ● -a substrate (11), the substrate (11) comprising silicon carbide (SiC) and having a first type of doping; ● A first crystal layer (12) on the substrate (11), the first crystal layer (12) comprising SiC and having a second type of doping different from the first type, ● On a first portion (121) of the first crystal layer (12): i. At least one crystal channel (13) containing SiC and having a doping of a first type, A source ohmic contact (14) comprising SiC and having a first type of doping on a first end (131) of each crystal channel (13); on the second end (132) of each crystal channel (13), a drain ohmic contact (15) comprising SiC and having a first type of doping, ● At least two bonding pads (16, 17) for forming ohmic contacts on a second portion (122) of the first crystal layer (12) adjacent to the first portion (121), ● At least one first conductive trace (18) extending over the first crystal layer (12) between each source ohmic contact (14) and at least one first pad (16) of the at least two pads (16, 17) for forming ohmic contacts, and ● At least one second conductive track (19) extending on the first crystal layer (12) between each drain ohmic contact (15) and at least one second pad (17) of the at least two pads (16, 17) for forming ohmic contacts, different from the at least one first pad (16), ● Such that each receiving area of the ion sensitive biosensor (0) is located on an exposed surface of at least one junction field effect transistor (1), preferably a crystal channel (13) of each junction field effect transistor (1).
  2. 2. The ion-sensitive biosensor (0) according to claim 1, further comprising a wall (31), preferably comprising PDMS, between the ends of each crystal channel or of a plurality of crystal channels (13), forming a receiving cavity for the analyte (4).
  3. 3. The ion-sensitive biosensor (0) according to claim 1, further comprising a plurality of walls, preferably comprising PDMS, between the ends (131, 132) of each crystal channel or of a plurality of crystal channels (13), forming a fluid circulation channel (32) for the analyte (4).
  4. 4. An ion-sensitive biosensor (0) according to any of claims 1to 3, further comprising a reference electrode (2) for at least partial immersion in an analyte (4).
  5. 5. A method of manufacturing an ion-sensitive biosensor (0) comprising at least one analyte (4) receiving area, characterized in that the method comprises manufacturing at least one junction field effect transistor (1) according to the following steps: ● Providing a stack (10) comprising: i. a substrate (11) comprising silicon carbide (SiC) and having a doping of a first type; -a first crystalline layer (12) on said substrate (11), comprising SiC and having a doping of a second type different from the first type; A second crystal layer (130) comprising SiC and having a first type of doping, located over the first crystal layer (12), and A third crystal layer (140) on the second crystal layer (130), the third crystal layer comprising SiC and having a first type doping; ● Depositing a first conductive layer on the third transistor layer (140), ● Etching the third transistor layer (140) to expose a partial region of the second transistor layer (130) with the first conductive layer as an etching mask, and forming at least a source ohmic contact (14) and a drain ohmic contact (15); ● Etching the first conductive layer to form: i. At least two bonding pads (16, 17) for forming ohmic contacts, At least one first conductive trace (18) extending over the first crystal layer (12) between each source ohmic contact (14) and at least one first pad (16) of the at least two pads (16, 17) for forming ohmic contacts, and At least one second conductive trace (19) extending over the first crystalline layer (12) between each drain ohmic contact (15) and at least one second pad (17) of the at least two pads (16, 17) for forming ohmic contacts different from the at least one first pad (16), followed by ● Etching the exposed portion of the second crystal layer (130) to form at least one crystal channel (13), ● Such that each receiving area of the ion sensitive biosensor (0) is located on an exposed surface of at least one junction field effect transistor (1), preferably a crystal channel (13) of each junction field effect transistor (1).
  6. 6. The manufacturing method according to claim 5, wherein the exposed portions of the second crystal layer (130) are etched to form a plurality of crystal channels (13) parallel and separated from each other.
  7. 7. The manufacturing method according to any one of the preceding claims 5-6, further comprising the steps of: ● A passivation layer (33) is deposited over at least a portion of the outer periphery of the etched exposed portion of the second crystal layer (130).
  8. 8. Use of an ion-sensitive biosensor (0) according to any of claims 1 to 4 for measuring the hydrogen ion concentration index (pH) of an analyte (4), in particular in vivo in a biological environment or in vitro in an environment with a pH value below 3 or above 8.

Description

Junction field effect transistor and related manufacturing method Technical Field The invention relates to the field of biosensors, having particularly advantageous applications in the diagnostic field. Background In recent years, silicon (Si) -containing field effect transistors have been developed deeply, which exhibit great potential in the field of biochemical detection based on an electrical measurement technique that is real-time, selective, highly sensitive and does not require a marker. However, the low biocompatibility and limited chemical inertness of silicon materials are major obstacles to the development of Field Effect Transistor (FET) biosensors in long-term applications in vitro and in vivo. More specifically, the limited reliability of silicon-containing field effect transistors limits their use in long-term detection applications, especially when the detection environment is in "harsh" conditions such as the human body. The presence of silicon in whatever form (nanowires, bulk materials, etc.) does not meet the reliability requirements, both because of its lack of long-term chemical stability (especially in physiological environments) and because of its biocompatibility drawbacks. For the biosensor for disposable detection, the defects of the silicon-based biosensor are acceptable, but for application scenes such as in-vitro and in-vivo long-term detection, the defects can not meet the use requirements. For example, there has been significant research and development effort in the industry to develop silicon-based hydrogen ion concentration index (pH) sensors for continuous in vivo monitoring. The silicon-containing ion-sensitive field effect transistors thus developed still fail to meet the standard requirements of the intended application. Therefore, it is now absolutely necessary to replace silicon with another material (which may be a semiconductor material) that has an inherent chemical stability, electrical properties comparable to silicon, and satisfactory biocompatibility. In this context, silicon carbide (SiC) is an ideal substitute material by virtue of its excellent mechanical properties, electrical properties, chemical stability and biocompatibility. Studies have demonstrated that SiC is chemically inert in physiological solutions better than silicon and is more biocompatible when immersed in physiological solutions. Furthermore, the use of SiC benefits from compatibility with the micromachining process of silicon materials. Therefore, in the field of biosensor development, silicon carbide is expected to replace silicon materials by virtue of the characteristics of silicon carbide over silicon, and is particularly suitable for multiple use or long-term application scenes. Awais et al have focused on such promising materials and studied the effect of pH on the transfer characteristics of silicon carbide nanowire-containing field effect transistors (see M. Awais, habeeb Mousa, K. Teker, influence of pH on the transfer characteristics of silicon carbide nanowire field effect transistors (SiCNW-FETs), published in journal of Material science: electronic materials, volume 32 (2021) pages 3431-3436). This document discloses a FET fabrication process based on SiC nanowires that are transferred onto an SOI (silicon on insulator) substrate for pH measurement. The proposed manufacturing method adopts a bottom-up strategy, namely transferring SiC nanowires first and then connecting. This leads to non-repeatability of the signal between nanowires-as nanowires are neither likely to be identical nor are they connected in different ways. Furthermore, it is important to propose a method that can uniformly fabricate silicon-containing FETs on a wafer scale, which will help reduce the risk of signal non-repeatability. The present invention therefore aims to provide a junction field effect transistor and/or an ion sensitive biosensor that overcomes the drawbacks of the prior art and/or employs a manufacturing method that may be full wafer, thereby reducing or even eliminating the risk of signal non-repeatability. Other objects, features and advantages of the present invention will become apparent upon reading the following description and upon reference to the accompanying drawings. It is to be understood that the invention may also include other advantages. Disclosure of Invention To achieve this object, a first aspect of the present invention relates to a junction field effect transistor comprising: a. a substrate comprising silicon carbide (SiC) and having a first type of doping; b. a first crystal layer on the substrate comprising SiC and having a second type of doping different from the first type; c. On the first portion of the first crystalline layer: i. At least one crystal channel comprising SiC and having a first type of doping, On a first end of each crystal channel, a source ohmic contact comprising SiC and having a first type of doping, On the second end of each crystal channel, a dr