Researchers develop high-performance heterojunction p-n diode

The research team developed a high-performance diamond/ε-Ga2O3 heterojunction p-n diode based on an ultra-wide bandgap semiconductor and achieved a breakdown voltage of over 3 kV. This work was published in Nano Letters.

The research was led by Professor Yichun Ye of the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS), along with researchers from Zhengzhou University, Nanjing University, Harbin Institute of Technology, and Yongjiang Research Institute.

Ultra-wide bandgap semiconductors such as Ga2O3 and diamond have shown remarkable potential in high-power applications due to their ultra-wide bandgap, high breakdown field, radiation tolerance, and carrier mobility. Bipolar devices, such as p-n diodes and bipolar junction transistors, have promising potential in the high-power electronics industry due to their ability to withstand reverse voltage currents.

However, effective bipolar doping in ultrawide bandgap semiconductors is limited by the substantial ionization energies of the dopants. To overcome this bottleneck, researchers proposed a heterozygous strategy. This approach integrates p-type diamond and n-type ε-Ga2O3 to fabricate a power pn diode.

Heteroepitaxial n-type ε-Ga2O3 films were grown on p-type diamond single crystal substrates by coordinating multi-domains and restricting the crystallization paths. This process reduces lattice mismatch. The heterojunction interface between ε-Ga2O3 and diamond is atomically sharp with no observable interfacial element diffusion, enabling high efficiency rectification and low reverse leakage current in the heterojunction diode.

Compared with previously reported diamond-based diodes, the fabricated diamond/ε-Ga2O3 heterojunction diodes exhibit remarkable rectifying properties with on-off ratios exceeding 108. Achieves maximum breakdown voltages of over 3,000 V even without edge termination.

Additionally, thermal boundary conductances of up to 64 MW/m2·K at 500 K were achieved, demonstrating the thermal management capabilities of the diamond/ε-Ga2O3 heterojunction diode.

In this study, we introduce an innovative methodology to fabricate high-performance ultra-wide bandgap semiconductor-based bipolar devices. The resulting device exhibits excellent breakdown voltage and efficient thermal management, making it highly suitable for ultra-high power applications.