We present the first results of a fabrication process aimed to produce IR grisms with high refractive index. Such devices are intended to implement a high resolution mode in the near IR camera-spectrograph, a user instrument at the focal plane of the Italian national telescope Galileo. Litho masking and anisotropic etching techniques have been employed to get, firstly, silicon gratings of suitable size for astronomical use, then warm bonding techniques will be used to obtain the final grisms in echelle configuration. The results of the laboratory test on the first prototype are presented.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.