Normally-Off AlGaN/GaN MOSHEMT as Lebel Free Biosensor

Abstract

In this paper, a systematic analytical model of biosensing parameters such as transfer characteristic, output characteristic, channel potential, transconductance-to-drain current ratio (gm/Ids),change in threshold voltage (ΔVTh), and sensitivity for a dielectric modulated normally off AlGaN/GaN metal oxide semiconductor high electron mobility transistor (MOSHEMT) is reported. A detailed analysis of the concept of gate cavity dielectric modulation in MOSHEMTs is performed with focus on the enhancement of sensing parameters to signify the presence of biomolecules such as Streptavidin, Biotin, and APTES. The accuracy of the model result is validated through Technology Computer Aided Design (TCAD) device simulator by incorporating nano gaps in MOSHEMT structure as well as suitable physics-based mathematical models are considered in simulation. Results highlighted a new view points and deep insight the design of Normally off AlGaN/GaN MOSHEMT-based dielectric modulated biosensors. Furthermore, this heterostructure provide a useful approach towards biomolecular detection and meeting the demand of interdisciplinary novel semiconductor device design.

Device optimization and sensitivity analysis of a double-cavity graded MgZnO/ZnO MOSHEMT for biomolecule detection

“…In this work, the total capacitance expression is developed using a simple gate capacitance model as described in sub-section 3.1. Once the gate capacitance model is developed, then the drain current and the sensitivity models are derived, as given in sub-section 3.2 and sub-section 3.3, respectively [23].…”

“…The gate capacitance effects are more pronounced in II-VI compound semiconductor devices than in siliconbased devices due to the layered structure capacitance, which certainly limits the V off and 2DEG channel density in MOSHEMTs [37]. It is commonly recognized from the literatures [22,23,38] that the cutoff voltage (V off )of any transistor is the sensing characteristic that is utilized to detect the biomolecules. A change in the cutoff voltage ( V off ∆ ) can be used to illustrate how the dielectric constant changes in response to the presence of neutral biomolecules in the cavity region of the device.…”

“…For the proposed MOSHEMT, we assumed that the immobilized target biomolecules are in the nanogap cavities, which are created on both the gate-source and gate-drain sides of the oxide under the gate region, as depicted in figure 1, and they serve as sensing sites. Without biomolecules under the gate region, indicating that the cavity has filled with air and the dielectric constant in the cavity is considered as  air = 1 [23]. The dielectric constant will change from unity to higher values when the target biomolecules are introduced in the sensing site.…”

“…Further, researchers were emphasized on MOSHEMT for biosensor applications. A limited number of analytical and simulation works were reported on AlGaN/GaN MOSHEMT to detect neutral biomolecules [20][21][22][23], PSA in human serum [24], and the pH of different electrolyte solutions [25]. With the aid of a charge control-based model, sensitivity analysis of a fabricated AlGaN/AlN/GaN MOSHEMT has been carried out with a focus on its biosensing capability to find an equivalent charge due to multiple bioanalytes that are commonly used biomarkers for aggressive diseases like kidney damage, breast cancer, prostate cancer, etc [26].…”

A Sensitivity Controllable Thermopile Infrared Sensor by Monolithic Integration of a N-channel Metal Oxide Semiconductor

“…MOSFET, as a basic element in CMOS analog and digital integrated circuit, can control output current between the source and the drain by changing the input voltage at the gate. Apart from this, due to the advantages of low cost, high stability, miniaturization and simple scalability, [23][24][25][26] MOSFET is widely applied in researches of biomolecules tracking, [27][28][29] heavy metal detection, [30][31][32] radio frequency sensing, [33][34][35] signal amplification 36,37 and so on.…”