Thin film silicon on insulator (TFSOI) devices have been studied for years. The advantages of TFSOI devices include: a reduction in junction capacitance, potentially lower junction leakage, a simpler process, and many other well documented advantages. However, other than some military/space applications, TFSOI circuits are not currently available in commodity products. One of the reasons TFSOI circuits are not wide spread is that there has not been a reliable source of TFSOI substrates. Recently, however, several suppliers of TFSOI substrates, both SIMOX and bonded and etch-backed wafers (BESOI), have made significant improvements in their material quality and are increasing capacity to meet expected demands. In this paper, we will discuss the major materials issues and how these issues impact either the TFSOI device performance or the process integration. In addition, we will present gate oxide integrity data as well as device results from these TFSOI substrates.