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Influence of conductivity and dielectric constant of water-dioxane mixtures on the electrical response of SiNW-based FETs.

Mescher M, Brinkman AG, Bosma D, Klootwijk JH, Sudhölter EJ, de Smet LC - Sensors (Basel) (2014)

Bottom Line: It was found that for liquid gating smaller potentials are needed to obtain similar responses of the nanowire compared to back gating.In the case of back gating, the applied potential couples through the buried oxide layer, indicating that the associated capacitance dominates all other capacitances involved during this mode of operation.Next, the devices were exposed to mixtures of water and dioxane to study the effect of these mixtures on the device characteristics, including the threshold voltage (V(T)).

View Article: PubMed Central - PubMed

Affiliation: Chemical Engineering, Delft University of Technology, 2628 BL Delft, The Netherlands. mmescher@gmail.com.

ABSTRACT
In this study, we report on the electrical response of top-down, p-type silicon nanowire field-effect transistors exposed to water and mixtures of water and dioxane. First, the capacitive coupling of the back gate and the liquid gate via an Ag/AgCl electrode were compared in water. It was found that for liquid gating smaller potentials are needed to obtain similar responses of the nanowire compared to back gating. In the case of back gating, the applied potential couples through the buried oxide layer, indicating that the associated capacitance dominates all other capacitances involved during this mode of operation. Next, the devices were exposed to mixtures of water and dioxane to study the effect of these mixtures on the device characteristics, including the threshold voltage (V(T)). The V(T) dependency on the mixture composition was found to be related to the decreased dissociation of the surface silanol groups and the conductivity of the mixture used. This latter was confirmed by experiments with constant conductivity and varying water-dioxane mixtures.

No MeSH data available.


Related in: MedlinePlus

(a) Schematic representation of the experimental setup (not to scale). Atop of the high-doped (1020 cm−3) silicon back gate (A) and a 300 nm thick buried oxide layer (B), the low-doped (1016 cm−3) silicon nanowire is located (C). The ends of the nanowire consist of high-doped (1020 cm−3) silicon and form the source and drain contacts (D), which were contacted via aluminum contacts (E). The source, drain and back gate contacts were insulated using a 100 nm thick silicon nitride passivation layer (F), such that the nanowire and a certain area around it can be exposed to the solution of interest (G). Furthermore, the nanowire is covered with an 8 nm thick thermal silicon dioxide layer (H). An Ag/AgCl electrode (I) was placed at a fixed position in the solution; (b) Photograph of the box used for the electrical characterization. The cables and tubing are left out for clarity.
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f1-sensors-14-02350: (a) Schematic representation of the experimental setup (not to scale). Atop of the high-doped (1020 cm−3) silicon back gate (A) and a 300 nm thick buried oxide layer (B), the low-doped (1016 cm−3) silicon nanowire is located (C). The ends of the nanowire consist of high-doped (1020 cm−3) silicon and form the source and drain contacts (D), which were contacted via aluminum contacts (E). The source, drain and back gate contacts were insulated using a 100 nm thick silicon nitride passivation layer (F), such that the nanowire and a certain area around it can be exposed to the solution of interest (G). Furthermore, the nanowire is covered with an 8 nm thick thermal silicon dioxide layer (H). An Ag/AgCl electrode (I) was placed at a fixed position in the solution; (b) Photograph of the box used for the electrical characterization. The cables and tubing are left out for clarity.

Mentions: SiNW-FETs were produced as reported previously [36]. Briefly, the nanowires (p-doped at a concentration of 1016 cm−3 to assure semiconducting behaviour) are 3 μm in length, 300 nm in width and 40 nm in height and are covered with a silicon dioxide gate oxide with a thickness of 8 nm. The thickness of the buried oxide (BOX) layer is 300 nm. The devices were wire bonded and covered with a micro fluidic device. The setup is shown in Figure 1.


Influence of conductivity and dielectric constant of water-dioxane mixtures on the electrical response of SiNW-based FETs.

Mescher M, Brinkman AG, Bosma D, Klootwijk JH, Sudhölter EJ, de Smet LC - Sensors (Basel) (2014)

(a) Schematic representation of the experimental setup (not to scale). Atop of the high-doped (1020 cm−3) silicon back gate (A) and a 300 nm thick buried oxide layer (B), the low-doped (1016 cm−3) silicon nanowire is located (C). The ends of the nanowire consist of high-doped (1020 cm−3) silicon and form the source and drain contacts (D), which were contacted via aluminum contacts (E). The source, drain and back gate contacts were insulated using a 100 nm thick silicon nitride passivation layer (F), such that the nanowire and a certain area around it can be exposed to the solution of interest (G). Furthermore, the nanowire is covered with an 8 nm thick thermal silicon dioxide layer (H). An Ag/AgCl electrode (I) was placed at a fixed position in the solution; (b) Photograph of the box used for the electrical characterization. The cables and tubing are left out for clarity.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3958210&req=5

f1-sensors-14-02350: (a) Schematic representation of the experimental setup (not to scale). Atop of the high-doped (1020 cm−3) silicon back gate (A) and a 300 nm thick buried oxide layer (B), the low-doped (1016 cm−3) silicon nanowire is located (C). The ends of the nanowire consist of high-doped (1020 cm−3) silicon and form the source and drain contacts (D), which were contacted via aluminum contacts (E). The source, drain and back gate contacts were insulated using a 100 nm thick silicon nitride passivation layer (F), such that the nanowire and a certain area around it can be exposed to the solution of interest (G). Furthermore, the nanowire is covered with an 8 nm thick thermal silicon dioxide layer (H). An Ag/AgCl electrode (I) was placed at a fixed position in the solution; (b) Photograph of the box used for the electrical characterization. The cables and tubing are left out for clarity.
Mentions: SiNW-FETs were produced as reported previously [36]. Briefly, the nanowires (p-doped at a concentration of 1016 cm−3 to assure semiconducting behaviour) are 3 μm in length, 300 nm in width and 40 nm in height and are covered with a silicon dioxide gate oxide with a thickness of 8 nm. The thickness of the buried oxide (BOX) layer is 300 nm. The devices were wire bonded and covered with a micro fluidic device. The setup is shown in Figure 1.

Bottom Line: It was found that for liquid gating smaller potentials are needed to obtain similar responses of the nanowire compared to back gating.In the case of back gating, the applied potential couples through the buried oxide layer, indicating that the associated capacitance dominates all other capacitances involved during this mode of operation.Next, the devices were exposed to mixtures of water and dioxane to study the effect of these mixtures on the device characteristics, including the threshold voltage (V(T)).

View Article: PubMed Central - PubMed

Affiliation: Chemical Engineering, Delft University of Technology, 2628 BL Delft, The Netherlands. mmescher@gmail.com.

ABSTRACT
In this study, we report on the electrical response of top-down, p-type silicon nanowire field-effect transistors exposed to water and mixtures of water and dioxane. First, the capacitive coupling of the back gate and the liquid gate via an Ag/AgCl electrode were compared in water. It was found that for liquid gating smaller potentials are needed to obtain similar responses of the nanowire compared to back gating. In the case of back gating, the applied potential couples through the buried oxide layer, indicating that the associated capacitance dominates all other capacitances involved during this mode of operation. Next, the devices were exposed to mixtures of water and dioxane to study the effect of these mixtures on the device characteristics, including the threshold voltage (V(T)). The V(T) dependency on the mixture composition was found to be related to the decreased dissociation of the surface silanol groups and the conductivity of the mixture used. This latter was confirmed by experiments with constant conductivity and varying water-dioxane mixtures.

No MeSH data available.


Related in: MedlinePlus