Diamond-enhanced GaN transistors in heat management

Diamond is a material that yields the highest thermal conductivity, and the use of diamond as a substrate for GaN transistors has more than doubled heat dissipation efficiency compared to traditional methods. This development not only enhances the performance and reliability of high-power, high-frequency electronic devices but also signifies a major step towards more sustainable and efficient electronic systems.

The crucial aspect of their research lies in the use of diamond as a substrate for these transistors. Because of its tightly packed crystal structure, diamond has unparalleled thermal conductivity.

The challenge of heat in miniaturised semiconductors

As semiconductor devices become increasingly miniaturised, they face a growing challenge – rising power density and the accompanying heat generation. These factors can adversely affect the performance, reliability, and lifespan of the devices. Thus, efficient thermal management emerges as a key concern in the semiconductor industry.

Diamond, holding the title for the highest thermal conductivity among all natural materials, presents itself as an ideal candidate for a substrate material. However, the practical application of diamond has been limited due to the challenges in bonding it with GaN elements.

A diamond 3C-SiC layer breakthrough

The research team, led by Associate Professor Jianbo Liang and Professor Naoteru Shigekawa have successfully fabricated GaN High Electron Mobility Transistors (HEMTs) using diamond as a substrate.

This novel technology boasts more than double the heat dissipation performance compared to transistors of the same shape fabricated on a silicon carbide (SiC) substrate.

To harness the high thermal conductivity of diamond effectively, the researchers introduced a 3C-SiC layer, a cubic polytype of silicon carbide, between the GaN and diamond. This technique remarkably reduces the thermal resistance at the interface, enhancing heat dissipation efficiency.

Implications for the industry

This advance holds significant potential for the semiconductor industry, particularly in fields requiring high-power, high-frequency operations such as 5G communication base stations, weather radar, and satellite communications. Additionally, it finds applications in microwave heating and plasma processing.

Improved thermal management and reduced CO2 emissions

Professor Liang emphasises the wider impact of this technology, noting its capacity to considerably lower CO2 emissions. He also points out its potential to transform the development of power and radio frequency electronics through enhanced thermal management capabilities.

The integration of GaN transistors with diamond substrates not only addresses the critical issue of heat management in miniaturised devices, but it also paves the way for more sustainable and efficient electronic systems in the future – marking a significant step forward in semiconductor technology.

This research from Osaka Metropolitan University may well be a cornerstone in the evolution of semiconductor technology, demonstrating that diamonds have much more to offer beyond their aesthetic appeal.