GaN on Si

(III-V and III-N materials and devices)

At mm-wave frequencies, silicon-based devices are outperformed by novel semiconductor technologies including the III-N (e.g., GaN) and III-V (e.g., InP) material systems. To reduce their cost and, potentially, environmental impact, there is a high interest in integrating these materials onto large-scale Si wafers.

Heterointegration brings plenty of previously unseen physical phenomena related to the interfaces formed by the III-V or III-N with Si and the complex multilayer material stack. These effects can lead to unwanted degradation of the devices’ performance, notably from the perspective of substrate loss and trapping [1][2].

At UCLouvain, we consider these innovative technologies with a bottom-up approach to provide engineering guidelines to our industrial partners. A fine understanding of the material physics and interfaces is gained via TCAD simulations and/or electrical measurements of multilayer substrates (MOS/MIS capacitors) [3][4]. The insights then percolate to the device level (small-signal equivalent circuit extraction, especially parasitics) and further to simple demonstrator circuits [5]. The full skillset available in our group is put to use, from the fabrication of simple test structures in our cleanroom facilities, wideband RF characterization to the design of complete circuits in state-of-the art technologies.