AlGaN Channel High Electron Mobility Transistors with Ultra-Low Drain-Induced-Barrier-Lowering Coefficient
The conventional AlGaN/GaN high electron mobility transistor (HEMT), the AlGaN/GaN/AlGaN HEMT, and the AlxGa1−xN/AlyGa1−yN HEMT are fabricated on sapphire substrates to study the drain-induced barrier-lowering (DIBL) effect. It is found that the AlxGa1−xN/AlyGa1−yN HEMT with AlGaN channel has the lowest DIBL coefficient of 6.7 mV/V compared with the other two HEMTs. This is attributed to the best two-dimensional electron gas confinement of the AlxGa1−xN/AlyGa1−yN structure. This opinion is further confirmed by the conduction band diagrams and electron distribution calculated from the one-dimensional Poisson—Schrodinger equation.
Let W be a UHF algebra and sQ(D) the disk algebra. If W = [U,ll >1 I ]Jand a is a product-type automorphism of W which leaves each 21,, invariant, then a defines an embedding t1 2>(D) n+ 1 D The inductive limit of this system is a Banach algebra whose maximal ideal space is closely related to that of the disk algebra if the Connes spectrum F(a) is finite.