Figure 2
(a) Cross-sectional representation of the theoretical modeling 2DHG diamond MOSFET with the fixed interface charge sheet model close to surface in the FETs diamond substrate where LGD= 4 μm, Lch = 4 μm and WG = 25 μm. The upper section illustrated the negative interface charge in the ALD Al2O3. (b), (c), (d) The band of the C–H diamond becomes upward near the Al2O3/C-H diamond interface. In the bulk, however, Fermi level Ef is fixed at 1.7 eV from the conduction band minimum corresponding to the position of nitrogen donor level (1.7 eV), which are common in the following three models withe negative, neutral, and positive interface charge sheets. (b) The negative interface charge density of 5 x 1012 cm-2. The valence band maximum crosses Fermi level near the Al2O3/diamond interface indicating a strong inversion layer. (c) For the no interface charge model, the valence band maximum is located at 1.8 eV from the Fermi level at the interface. It indicates a weak inversion layer. (d) The positive interface charge density of 1 x 1011 cm-2. The valence band maximum forms an upward band bending, but cannot reach the Fermi level. It is located at 2.1 eV from the Fermi level at the interface. The band diagram is also classified as a weak inversion.
