Two types of FNO compounds (FNO and F3NO) were evaluated as candidates for new chemical vapor deposition (CVD) chamber cleaning gases. NF3 and C2F6 were measured as the reference. Like NF3, as these gases have no carbon in their molecules, no perfluoro carbon (PFC) is thought to be emitted. FNO is a compound highly susceptible to hydrolysis. F3NO is expected to decompose more easily than NF3 in the atmosphere because its N-F bond has been weakened by introducing an N=O bond into the molecule. Hence, the contribution to global warming of these compounds is expected to be small. Performance of these gases was evaluated by measuring their etch rates and their exhaust gases. The results showed that the etch rate of F3NO is virtually the same as that of NF3, whereas the etch rate of FNO is about 1/2 that of NF3. However, from the results of exhaust gas analysis, it was found that an unexpected side reaction had occurred in the chamber, and therefore, it was confirmed that it is important to take this property into account in designing applications. (C) 2003 The Electrochemical Society.