Abstract: Improved high-low multi-frequency（HLMF） and average bottom-top-pulse（ABTP） CP techniques have been proposed for characterizing the interface traps in ultra-thin gate oxide CMOS devices.It is successfully demonstrated that these two improved CP techniques work fine to separate the leakage current from Icp for MOSFETs.Moreover,the typical characteristics of the corrected Icp are discussed.Since the static mode is used to collect leakage in ABTP,the large noise of the corrected Icp tail at the lager negative Vbase emerges.From comparison,it is found that HLMF has higher precision than ABTP and can be regarded as the reference method for improving accuracy of CP in ultrathin gate oxide CMOS devices.