GaN CAVET Epi Structure *S

Gallium nitride (GaN) is gradually becoming a research hotspot in the field of power electronics due to its excellent performance characteristics, such as high electron mobility, high electron saturation rate, high temperature resistance, and high thermal conductivity. Vertical GaN power transistors, especially GaN current aperture vertical electron transistors (CAVETs), as a new type of power device structure, combine the advantages of two-dimensional electron gas (2DEG) of HEMTs with vertical device structure design, which can improve the device blocking voltage without increasing the chip size. PAM-XIAMEN can provide GaN CAVET epitaxial growth services, which can be referred to in the following sapphire based structures. You can also send customized epistructures to our email: [email protected] to elvaluate and quote.

1. GaN CAVET Epistructure on Sapphire Substrate

2. Comparison of Regrowth between MOCVD and MBE Processes in CAVET

Researchers investigate the regrowth processes using MOCVD and MBE separately on GaN CAVET fabrication. A template containing p-GaN current blocking layer was prepared based on sapphire substrate. After forming the pore structure through etching process, the GaN channel layer and AlGaN barrier layer were grown using MOCVD and MBE techniques, respectively. The interface characteristics of the regrown layer were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).

The experiment found that the diffusion of magnesium (Mg) element in p-GaN during MOCVD process significantly reduces the mobility of 2DEG, and the CAVET devices prepared by it have high leakage current problems; while the MBE technology can effectively suppress Mg diffusion, achieve better 2DEG characteristics and device turn-on performance, but the problems of high gate leakage current and off state leakage still need to be solved. Future research will focus on optimizing the MOCVD process to reduce the influence of Mg diffusion, or improving the MBE regrowth conditions to suppress leakage current, and exploring pore preparation schemes using ion implantation instead of etching. At the same time, device performance will be further improved by planarization of pore regions or adjusting aspect ratios.

3. Advantages and Applications of GaN CAVETs

The core advantages of GaN CAVET are reflected in its unique structural design and material properties:

Firstly, the N-polarity CAVET embeds a high blocking electric field inside the device through vertical electric field distribution, effectively suppressing the current dispersion and breakdown risk caused by surface states. At the same time, its naturally formed two-dimensional electron gas (2DEG) can achieve low threshold voltage and contact resistance without additional doping. Combined with the effective suppression of Mg2+ ion diffusion by AlN barrier layer, the uniformity and stability of the current barrier layer are further improved, with both high breakdown voltage and low current dispersion characteristics.

Secondly, CAVET integrates the high carrier mobility of AlGaN/GaN heterojunction with optimized electric field distribution of vertical topology, significantly improving power density compared to transverse HEMT devices. At the same time, the high electron mobility and breakdown electric field of GaN material itself make it an ideal choice for high-power electronic devices.

In the future, by optimizing CBL growth technology, device structure, and ion implantation parameters, it is expected to further improve breakdown voltage, reduce leakage current, and expand its application potential in high-power and high-voltage scenarios such as electric vehicles, smart grids, and high-frequency communication.

Whether you need GaN epitaxy for research or for industrial applications, please contact us email at [email protected] and [email protected].