Novel transport mechanism of SiGe dot MOS tunneling diodes

The blockage of the hole transport due to the excess hole in SiGe quantum dots was observed in the metal-oxide-semiconductor (MOS) tunneling diodes for the first time. The hole tunneling current from Pt gate electrode to p-type Si dominates the inversion current at the positive gate bias and is seven order of magnitude higher than the Al gate/oxide/p-Si device. The SiGe quantum dots confine the excess holes in the valence band, and form the repulsive barrier to reduce the hole transport current from Pt to SiGe quantum dots by three order of magnitude as compared to the Pt/oxide/p-Si device. This repulsive barrier also reduces the hole tunneling current from SiGe quantum dots to Pt for the accumulation current at positive gate bias.