Characterization of front and back Si-SiO2 interfaces in thick- and thin-film silicon-on-insulator MOS structures by the charge-pumping technique

It is shown that the charge-pumping technique can be successfully applied to SOI structures, directly providing important and reliable information about the quality of both front- and back-gate interfaces. The possibility of performing measurements on a transistor level makes direct correlation with other MOS characteristics and material parameters possible. In particular, the ability of this technique to perform measurements on thin-film transistors and to separate the information from front and back gates makes it indispensable for characterization of advanced SOI CMOS structures. Although the technique was demonstrated only on 5-μm channel length devices, it has sufficient sensitivity to be applicable to transistors of micrometer and submicrometer dimensions. Charge-pumping measurements on laser-recrystallized SOI MOSFETs showed that the front interface is only slightly deteriorated compared to that of bulk MOSFET devices, while the back interface is of a substantially lower quality, with about 10 times higher interface trap densities