This paper presents the design, fabrication, and characterization of on silicon integrated micro-transformers for high frequency power applications. This device has stable characteristic of L versus f up to frequencies higher as 50 MHz. The design is improved, so that the electrical resistance of coils is reduced and current capability is increased. The microtransformer shows an inductivity of about 50 nH, resistance of 350 mΩ and can be applied for current up to 1.5 A