GaN-on-Si: 5G opens up new market opportunities – An interview with STMicroelectronics

In the last decade, GaN has experienced significant adoption by the Radio-Frequency (RF) industry owing to its higher power output at high frequencies, and to its smaller footprint. As reported in “RF GaN 2019: Applications, players, devices, and technologies” from Yole Développement (Yole), the overall GaN RF market is expected to reach $2B by 2024, driven mainly by two applications: wireless infrastructure and defense. Yole and its partner Knowmade are following the RF GaN industry and deliver their vision of the market evolution and competitive landscape in a wide collection of reports, including for example, RF GaN 2019 – Patent Landscape Analysis performed by Knowmade.

Currently dominating the GaN RF industry, GaN-on-SiC penetrated the fourth generation (4G) Long-Term Evolution (LTE) Wireless infrastructure market and is expected to be deployed in RRH architectures in 5G’s sub-6GHz implementations. Recently, there have been attempts to challenge GaN solutions with cost-efficient and continuously optimized LDMOS in 5G sub-6GHz active antennae and massive Multiple Input, Multiple Output (MIMO) deployments. This could happen at the expense of reduced efficiency, therefore increased power consumption, which is not sustainable for a large-scale rollout of 5G.  In this context, GaN-on-Si stands as a potential challenger with possible expansion to production on 8-inch wafers, and promises cost-efficient solutions for commercial markets.

In the GaN-on-Si RF industry, STMicroelectronics (ST) is a leading actor in collaboration with MACOM targeting global 5G base station applications with expansion of production capacity of 150mm GaN-on-Silicon and further expansion to 200mm. Furthermore, ST has announced its interest in GaN-on-Si handsets, which could open exciting new market opportunities for the GaN RF business. Today, Yole has the opportunity to meet Filippo Di Giovanni, Director Strategic Marketing, Innovation & Key Programs for New Materials and Power Solutions Division, Automotive Products Group, at STMicroelectronics to discuss the company’s technology status and roadmap for the coming years.

This interview has been conducted by Ezgi Dogmus, PhD., Technology & Market Analyst, Compound Semiconductors & Emerging Materials, and Hong Lin, PhD., Senior Technology & Market Analyst, Compound Semiconductors & Emerging Materials, at Yole.

Ezgi Dogmus (ED): Could you please introduce yourself to our readers? What are your responsibilities at STMicroelectronics?

Filippo Di Giovanni (FDG): My name is Filippo Di Giovanni. I am responsible for Strategic Marketing, Innovation and Key Programs in ST’s New Materials and Power Solution Division.

ED: So far, the majority of GaN RF products are based on GaN-on-SiC technology. Why did STMicroelectronics choose GaN-on-Si for your RF products?

FDG: GaN-on-Silicon is poised to displace LDMOS for RF products because it offers significant cost advantages vs. competitors’ GaN-on-SiC solutions. In addition, ST’s GaN-on-Si enables faster ramp-up and easier scalability for RF products.

ED: Do you develop GaN-on-SiC-based products as well? How do you compare the two technologies?

FDG: Each one has its own advantages and drawbacks. GaN-on-Si is easily scalable to 8” today. This is a very important pre-requisite to ramp up production in order to serve the nascent 5G market which we anticipate will be a high-volume market in time.

ED: What will be STMicroelectronics GaN-on-Si RF product portfolio?

FDG: The ST GaN-on-Si portfolio will cover the majority of the RF applications for Communication, RF Energy, and ISM.

ED: Will STMicroelectronics develop both MMIC and packaged discrete transistors?

FDG: Yes. As a customer-centric technology company, we’ll use our technology and expertise where the customer needs it.

Hong Lin (HL): What are the characteristics of ST’s GaN-on-Si RF products?

FDG: ST’s GaN-on-Si products deliver high power gain and efficiency, cost-efficiency and easy to use pre-distortion to correct linearity issues. 

HL: What is the technology roadmap of GaN-on-Si RF products in terms of technology node regarding the 5G mm-wave applications?

FDG: ST’s priority today is on sub-6GHz development; simulations on scaled-down variants are ongoing

HL: According to Yole Développement, devices will use epi wafer developed by IQE and be produced on 6” wafers in STMicroelectronics’s Catania fab, though the process is compatible with 8” if there is enough demand. Can you confirm this information?

FDG: ST’s RF GaN-on-Si production line is the Catania 150mm Fab. We cannot disclose our Epi wafer supplier.

HL: Could you tell us when do you expect the transition to 8 inch and what the key challenges are for this transition? Can you disclose the current and targeted capacity of STMicroelectronics’ GaN-on-Si process?

FDG: ST has a plan to expand our manufacturing line to 200mm to support our technology roadmap and anticipated volume growth.

HL: What is the status of your GaN-on-Si power device development? Is there any synergy with your GaN-on-Si RF development?

FDG: Power GaN will be intrinsically normally-off so it will address the power conversion domain where ST is the market leader. There is no synergy with the RF version.

HL: What is your timeline for commercialization of GaN-on-Si RF products?

FDG: By 2020.

HL: What are your perspectives about integrated GaN-on-Si RF modules? Do you plan to develop integrated GaN RF solutions?

FDG: Yes, we anticipate creating GaN-on-Si RF modules by exploiting synergies with other ST product groups.


Filippo Di Giovanni has been with STMicroelectronics for over 30 years, involved with power transistor technologies starting from bipolars, used extensively at that time in CRT horizontal deflection and lighting applications, to MOSFETs. As Technical Marketing Manager he helped introduce the first strip-based MOSFETs, both low voltage and high voltage, among the first in the industry making ST a reference for competitors.
At the end of the nineties, Filippo Di Giovanni started introducing ST’s own “Super-junction” high-voltage MOSFETs, named MDmeshTM, thanks to which ST has become one of the strongest market players in this field.
In the same position he pushed the introduction of planar IGBTs, still used today in the home appliance domain, and paved the way for developing the first generation of Trench field-stop IGBTs.
Starting from 2012 he drove the development of the first 1,200V silicon carbide (SiC) MOSFETs that have enabled ST to become today undisputable market leader, even in the nascent EV market.
His experience spans also to gallium nitride on silicon (GaN-on-Si) for both power conversion and RF domains.
Filippo has attended several conferences and workshops dedicated to power transistors, such as PCIM and APEC. At the moment he is also a member of the team handling the development collaboration of GaN-on-Si with important industry partners.


As a Technology & Market Analyst, Compound Semiconductors, Ezgi Dogmus, PhD is member of the Power & Wireless division at Yole Développement (Yole).
She is daily contributing to the development of these activities with a dedicated collection of market & technology reports as well as custom consulting projects.
Prior Yole, Ezgi was deeply involved in the development of GaN-based solutions at IEMN (Lille, France). Ezgi also participated in numerous international conferences and has authored or co-authored more than 12 papers.
Upon graduating from University of Augsburg (Germany) and Grenoble Institute of Technology (France), Ezgi received her PhD in Microelectronics at IEMN (France).

Hong Lin, PhD., Senior Technology & Market Analyst, Yole Développement

Hong Lin, PhD works at Yole Développement (Yole), as a Senior Technology and Market Analyst, Compound Semiconductors within the Power & Wireless division since 2013. She is specialized in compound semiconductors and provides technical and economic analysis. Before joining Yole Développement, she worked as R&D engineer at Newstep Technologies. She was in charge of the development of cold cathodes by PECVD for visible and UV lamp applications based on nanotechnologies. She holds a Ph.D in Physics and Chemistry of materials.

Related reports:

RF GaN Market: Applications, Players, Technology and Substrates 2019
GaN RF market growth is fed by military and 5G wireless infrastructure applications.

RF GaN 2019 – Patent Landscape Analysis
The RF GaN market is developing fast, driven by mm-wave, 5G and defense applications. Do current leading market players have the right IP portfolios to face huge opportunities for GaN devices?