G-Doping-Based Metal-Semiconductor Junction

Geometry-induced doping (G-doping) has been realized in semiconductors nanograting layers. G-doping-based p-p(v) junction has been fabricated and demonstrated with extremely low forward voltage and reduced reverse current. The formation mechanism of p-p(v) junction has been proposed. To obtain G-doping, the surfaces of p-type and p+-type silicon substrates were patterned with nanograting indents of depth d = 30 nm. The Ti/Ag contacts were deposited on top of G-doped layers to form metal-semiconductor junctions. The two-probe method has been used to record the I-V characteristics and the four-probe method has been deployed to exclude the contribution of metal-semiconductor interface. The collected data show a considerably lower reverse current in p-type substrates with nanograting pattern. In the case of p+-type substrate, nanograting reduced the reverse current dramatically (by 1-2 orders of magnitude). However, the forward currents are not affected in both substrates. We explained these unusual I-V characteristics with G-doping theory and p-p(v) junction formation mechanism. The decrease of reverse current is explained by the drop of carrier generation rate which resulted from reduced density of quantum states within the G-doped region. Analysis of energy-band diagrams suggested that the magnitude of reverse current reduction depends on the relationship between G-doping depth and depletion width.

Automated summary

Geometry-induced doping (G-doping) has been successfully achieved in semiconductor nanograting layers, leading to the fabrication of p-p(v) junction with significantly low forward voltage and reduced reverse current. The formation mechanism of p-p(v) junction has been proposed, explaining the impact of G-doping depth and depletion width on the reduction of reverse current. Theoretical analysis shows that the decrease in reverse current is attributed to the lower carrier generation rate resulting from the reduced density of quantum states within the G-doped region.