EAG is Featured in Compound Semiconductor: Using SIMS to Scrutinise HEMTS
Using SIMS to Scrutinise HEMTs
From the buffer layer to the very top of the device, a novel form of SIMS can uncover troublesome impurities in GaN-on-silicon HEMTs.
BY TEMEL H. BUYUKLIMANLI AND CHARLES W. MAGEE
One of the devices attracting the most interest in the compound semiconductor manufacturing industry is the GaN-based HEMT. Its capability to operate at high voltages and deliver high powers at microwave frequencies makes it an attractive candidate for deployment in base stations, and in a range of defence applications, including radar.
The impressive performance of this wide bandgap HEMT stems from the specific material properties associated with GaN. Compared to GaAs-based materials, which have also been used for generating power in the microwave region, GaN has a larger peak electron velocity; a higher thermal stability; and a larger band gap. All of these traits make GaN a very appropriate material for the channel of a HEMT. In such structures it is often paired with AlGaN to form a two dimensional electron gas (2DEG), which lies at the very heart of the device, dictating its electrical characteristics.