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Environmentally Robust Biosensor Using Field Effect Transistors of Heteroepitaxial Diamond

使用异质外延金刚石场效应晶体管的环境鲁棒性生物传感器

基本信息

批准号：
09555103
负责人：
KAWARADA Hiroshi
金额：
$ 7.68万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

In this research, ion sensitive field effect transistors (ISFETs) have been fabricated on the hydrogen terminated (H-terminated) diamond surface resistant to electrochemical environment and operated as transducers of biosensors.1. The electrolyte solution gate FETs have been formed on H-terminated surfaces. The gate structure is just thet H-terminated diamond exposed to directly. This type of FET structure where semiconductor surface is exposed to electrolyte solution is firstly developed in the world. Compared with conventional ISFET, the higher current controllability is achieved.2. The FETs exhibit ideal current-voltage characteristics in not only homoepitaxial and heteroepitaxial diamonds, but also polycrystalline diamonds which is easier to synthesize. In the current-voltage characteristics, perfect pinch-off and the saturation of drain current have been measured. The leakage current at the off state is extremely small and the current ratio between on-off is more than 4 orders of magnitude. The FETs operate stably in the above mentioned characteristics between pH 1-14.3. The threshold voltages of the FETs are independent from pH values. From this result, an appropriate ion sensitive base can be immobilize on the pH insensitive surface leading to high selective molecular recognition.4. On the other hand, the threshold voltages strongly depend on the density of Cl ions in the solution and vary by 30-60 mV according to the density change by one order The Cl ion detection has been observed from 1 Mol/L to 10^<-6> Mol/L exhibiting the possibility of Cl ion sensitive FET.The diamond solution gate FET has been developed for the first time. Their operation in hard environment has been also confirmed and the highly sensitive detection of Cl ions has been achieved.

在这项研究中，在耐电化学环境的氢端（H端）金刚石表面上制备了离子敏感场效应晶体管（ISFET），并作为生物传感器的换能器。1.电解质溶液栅极FET已经形成在H端表面上。栅极结构就是直接暴露在氢原子中的金刚石。这种将半导体表面暴露在电解质溶液中的FET结构在世界上尚属首次。与传统ISFET相比，具有更高的电流可控性. FET不仅在同质外延和异质外延金刚石中表现出理想的电流-电压特性，而且在更容易合成的多晶金刚石中也表现出理想的电流-电压特性。在电流-电压特性中，测量了完全夹断和漏极电流饱和。关断状态下的漏电流极小，通断电流比大于4个数量级。FET在pH 1-14.3之间以上述特性稳定地操作。FET的阈值电压与pH值无关。由此可见，合适的离子敏感性碱可以吸附在pH不敏感的表面上，从而实现高选择性的分子吸附.另一方面，阈值电压强烈依赖于溶液中Cl离子的浓度，随浓度变化一个数量级，阈值电压变化30-60 mV。在1 ~ 10 μ Mol/L范围内观察到Cl离子的检测<-6>，显示出Cl离子敏感FET的可能性。它们在硬环境中的操作也得到了证实，并实现了对Cl离子的高灵敏检测。