Ohmic co-doped GaN/InGaN tunneling diode grown by MOCVD

Abstract

Tunnel junctions (TJs) have recently been proposed as a solution for several III-nitride current problems and to enhance new structures. Reported III-nitride TJs grown by metalorganic chemical vapor deposition (MOCVD) resulted in backward diodes with rectifying behavior in forward bias, even with Mg and Si doping in 1020 cm−3. This behavior limits applications in several device structures. We report a TJ structure based on p+In0.15Ga0.85N/n+In0.05Ga0.95N, where the n-side of the junction is co-doped with Si and Mg and with electron and hole concentrations in the mid-1019 cm−3 for both the n and p dopants. Co-doping creates deep levels within the bandgap that enhances tunneling under forward biased conditions. The TJ structure was investigated on both GaN substrates and InGaN templates to study the impact of strain on the TJ I–V characteristics. The resulting TJ I–V and resistivities reported indicate the potential for this TJ approach in several device structures based on III-nitrides. We are not aware of any previous MOCVD grown TJs that show Ohmic performance in both forward and reverse biases.

A distinctive architecture design of lateral p–n type GaN ultraviolet photodetectors via a numerical simulation

“…A reasonable explanation is that the tunneling effect is closely related to the doping concentration of GaN and the applied voltage. In the case of high doping and large reverse bias, the possibility of tunneling can only occur when forming a sharp and narrow depletion layer [31][32][33]. To verify this hypothesis, the energy band diagrams for the cases with different doping concentrations and bias voltages are plotted in figure S4 in the supplementary material.…”