Abstract: Various embodiments of the present disclosure are directed towards a three-dimensional (3D) IC comprising semiconductor substrates with different bandgaps. The 3D IC chip comprises a first IC chip and a second IC chip overlying and bonded to the first IC chip. The first IC chip comprises a first semiconductor substrate with a first bandgap, and further comprises and a first device on and partially formed by the first semiconductor substrate. The second IC chip comprises a second semiconductor substrate with a second bandgap different than the first bandgap, and further comprises a second device on the second semiconductor substrate.

Abstract: A transistor includes a substrate, a semiconductor unit disposed on the substrate, a gate unit, a source electrode and a drain electrode. The gate unit includes a non-metal gate part disposed on the semiconductor unit, and a metal gate layer entirely enclosing the non-metal gate part. The drain and source electrodes are disposed respectively on two opposite sides of the gate unit.