Analysis of the key parameters of box creep process for advanced FDSOI devices

Since the 14nm node, miniaturization of devices fabricated with the Fully-Depleted-Silicon-On-Insulator (FDSOI) technology comes along with the introduction of new boosters. Among them, a process known as “box creep” enables to transfer stress from a top layer to an initially relaxed channel in order to increase the electron/hole mobility. This process takes advantage of the viscoelastic properties of the Buried OXide (BOX) at high temperature, typically above 1000°C. In this paper, we highlight the key material properties involved in this process by an analytical and numerical approach. We propose a proper methodology to extract these key properties from experimental data and give an example of application as a test case of this methodology.