Hydrogenated silicon (Si: H) film was grown by radio frequency plasma enhanced chemical vapor deposition (PECVD) method. The transition between hydrogenated amorphous silicon (a-Si: H) and hydrogenated microcrystalline silicon (mu c-Si: H) was characterized by X-ray diffraction analysis. A semiconductor system was used to measure low frequency noise (1/f noise) and random telegraph switching noise of Si: H films. The results show that the 1/f noise of mc-Si:H is 4 orders of magnitude lower than that of a-Si: H and no RTS noise was found in both films. It also shows that using mu c-Si: H instead of a-Si: H film as a sensing layer will enable the development of high performance uncooled microbolometer. (c) 2008 Published by Elsevier B. V.