6 April 2022
5G a significant market opportunity for GaN
Much of the 5G rollout to date has been in frequency bands more similar to existing 4G rather than taking full advantage of 5G’s higher frequencies, notes IDTechEx’s latest research report ‘Thermal Management for 5G 2022-2032’. The existing state of 5G has seen less technological innovation than might have initially been expected, with the promise of high-frequency, Gigabit download speeds, and millisecond latency yet to be realized in a major way. There is certainly more scope for technical development and hence opportunities for several technologies and materials, a critical one of which is wide-bandgap semiconductors, says IDTechEx. In particular, gallium nitride (GaN) has a significant opportunity within the 5G market, and this creates a downstream effect on other components such as die attach materials, the report adds.
LDMOS (laterally diffused metal-oxide semiconductor) devices have been the technology of choice for power amplifiers through the 4G era. These power amplifiers provide the crucial role of boosting the signal for transmission. The trouble is that, above about 4GHz, LDMOS starts to become inefficient (critical for telecoms infrastructure, as it directly impacts the energy consumption of the antenna). With much of 5G infrastructure being deployed alongside existing equipment, the energy consumption of telecoms towers is set to increase dramatically. The adoption of wide-bandgap semiconductors like GaN is one method for reducing this future impact. GaN provides greatly improved efficiency at higher frequencies (10% or more improvement, depending on the specific use-case).
GaN started being deployed in 4G networks with Huawei equipment, but it has seen only moderate adoption globally so far due to the increased price, lower manufacturing availability, and difficulty in integration with other components. However, it is far from niche technology developed by startup companies. For example, Japanese technology giant Sumitomo provides RF components to companies like Huawei including their GaN devices. With the growth of 5G continuing, especially for higher frequencies, IDTechEx expects a significant uptake in GaN over the next decade, especially for the higher end of the sub-6GHz infrastructure where higher powers are being used and component integration is not quite as challenging as it is in the millimeter-wave (mmWave) region. For this application, IDTechEx predicts a four-fold increase in GaN demand per year by the end of the decade.
The adoption of wide-bandgap semiconductors typically raises the junction temperature of devices and starts to bring more thermal management considerations. One critical failure point with thermal cycling is how the semiconductor device is connected, or the die attach material. Junction temperatures for GaN devices are often above 175°C. At this point we start to limit the options for typical solder materials, especially when lead-free is a requirement in most markets.
This is leading many players to consider sintering materials. Sintering involves the application of a (typically silver) paste that is heated, causing densification. The upshot is a more reliable connection with improved thermal conductivity. This has already started to be adopted in a big way in the electric vehicle (EV) market due to the transition to silicon carbide (SiC) and 800V platforms.
The key limitation historically has been the lack of commercial experience, long curing times, and the need for an inert atmosphere or higher pressures, but developments of these materials, greater market adoption, and the trend towards GaN could see sintering start to make a big impact in the 5G market too. IDTechEx expects a 10-fold increase in demand for sintering materials in 5G infrastructure by 2030. There is also great interest in the development of copper sintering materials rather than silver (due to the potentially reduced costs and improved performance), but this encounters the same issues that silver sintering had originally compared with solder.