Silicon on Insulator (SOI) technology has become one of the most promising technologies in semiconductor fabrication industry for its numerous advantages. This study presents merits and demerits of different SOIs presented in literatures and a comparative study is done based on several design and performance issues for low power applications. From the study it is found that Fully Depleted SOI MOSFET (FDSOI) technology is preferred due to its thin size, reduced leakage current and improved power consumption characteristics etc. compared to those of PDSOI and bulk silicon technology.