Effect of Microwave Annealing on the Interface Properties Between the Top Silicon and Buried Oxide Layers in Silicon-on-Insulator MOSFETs

In this paper, a post-annealing process that uses microwaves to remove the back-interface thermal damage at the interface between the top silicon layer and the buried oxide layer of a silicon-on-insulator (SOI) device caused during rapid thermal annealing (RTA) was studied. RTA, which is widely used in highly integrated short-channel silicon device manufacturing processes, deteriorates the electrical characteristics of SOI pseudo metal-oxide-semiconductor field-effect transistors (MOSFET) by affecting the interfacial properties between the top silicon and buried oxide layers. In order to replenish these interfacial properties, microwave annealing (MWA) was performed on the device under various conditions. Because MWA utilizes the direct energy transfer (DET) method, the RTA-induced thermal damage on the back interface was effectively removed despite a short processing time. The improvement was comparable to that of conventional thermal annealing at a higher temperature for a long period of time. Therefore, MWA is expected to be a very effective post-RTA heat-treatment technology for fabricating ultrathin-body SOI MOSFETs because of its low thermal budget.