Most gallium nitride (GaN) microwave transistors are import-restricted because these are highly strategic in nature and are used in radars, jammers, electronic warfare and even telecom infrastructure. These transistors amplify or boost the radio waves when sent from the transmitter in most wireless communication or military applications.
The costly silicon carbide (SiC) platform is used to realize nearly all of these GaN transistors; creating these devices on the GaN on silicon platform holds promise for volume and scale economies. But there are drawbacks to this strategy as well.
In a recent study, scientists at the Centre for Nano Science and Engineering (CeNSE) created and demonstrated a fully indigenous GaN on silicon microwave transistor for the first time in India. The transistors are entirely designed, manufactured, and tested at IISc, and the material stack or wafer is grown there.
The team’s accomplishment of 8W of power at 10 GHz is strategically significant. For this, the knowledge of fabricating different unit process modules was created, and the atomic layer-by-layer deposition of the material stack was thoroughly examined and optimized.
The researchers tuned a basic GaN feature known as “polarization” to build the material-stack’s energy environment. This aided them in eliminating purposeful contaminants like iron or carbon that would otherwise need to be introduced to such wafers in order for them to tolerate high voltages.
For the first time, the team has demonstrated microwave power transistors based on GaN-on-silicon which do not contain any intentional carbon or iron impurities.
