Double Gate MOSFET

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Figure 1. Schematics structure of the simulated layer structure

We simulated a structure which is depicted in figure 1., which is built from Si and $SiO_2$. The channel is built from undoped $Si$, while the oxide layer is a thin $SiO_2$ layer.

Zero-bias properties

The conduction band structure without bias is depicted in figure 2.

	\node[inner sep=0pt] (russell) at (0,2)
	\draw [|->] (0.35, -0.75) --(0.35, 3.2);
	\draw [|->] (-4, 1.2) --(5, 1.2);
	%\draw [draw=white,fill=white] (0,-2) rectangle (1,-0.1);

Figure 2. Schematics of the double-gate MOSFET's conduction-band

If we make a slice of the conduction band in the X and Y directions as it is plotted in figures 3., 4. we are creating a quantum confinement of electrons in the channel region. If we calculate the electron density in the channel region it makes a huge difference, whether we calculate with quantum mechanical effects or not.


Figure 3. Conduction band profile in the Y direction


Figure 4. Conduction band profile in the Y direction


Figure 5. Classically calculated electron density


Figure 6. Quantum mechanically calculated electron density in the channel


Figure 7. Electron density in the channel with and without quantum-mechanical correction

Due the fact that the electron density in the channel controls the current between the drain source contacts, it is important to compare the tho models with each other, which is plotted in figures 5, 6. The used quantum-mechanical model was simple effective mass model in the channel region.

The electron density profiles in the sample are also compared in figure 7. It shows that including quantum mechanical effects the electron density is shifted in positive direction, while it gets wider.

  • physicswiki/semiconductors/dgatemosfet/dgatemosfet.txt
  • Last modified: 2019/04/09 12:48
  • by zoltan.jehn