In this work, the diffusion mechanisms of both boron and phosphorus dopants are analyzed when they are diffused or ion-implanted and activated/diffused in high-index silicon substrates. Si(1 1 4) and Si(5 5 12) wafers are reported as highly promising substrates for the development of novel quantum structures especially for MOS devices. In order to obtain the final dopant distribution an electrochemical profiler was utilized. Because it is well known the lack of reported experimental data regarding the doping mechanism in these high-index silicon substrates, Si(0 0 1) and Si(1 1 1) substrates were utilized as reference. The experimental work was conducted varying the following parameters: temperature, doses, energy, tilt angle, silicon oxide masking film thickness, ambient and activation method; the thermal activation/diffusion of the impurities was specially evaluated because they influence in the final distribution of dopants. The doping profile of each experimental condition was extracted and discussed in terms of the anomalous effects: OED (Oxidation-Enhanced Diffusion), TED (Transient Enhanced Diffusion), and ion channeling. A test chip was fabricated to measure process and device parameters which were related to the profiles measured. The MOS (Metal-Oxide-Semiconductor) transistor performance fabricated in the high index silicon was evaluated and compared to those fabricated in the low index silicon substrates. From the results presented in this work, we can state: -If the diffusion process is not conducted under oxidation, then diffusivity (D) in high index silicon substrate is independent on the crystal orientation; however, under oxidation conditions, it process becomes a strong function of crystal orientation and exhibits the tendency: D(0 0 1)<D (1 1 4) <D(5 5 12)<D (1 1 1) . -Any anomalous effect can be observed when diffusion process is conducted under high temperature for very long time. - If silicon oxide masking film is thicker than 600 Å, then channeling is minimized. This result is quite interesting since it reveals that it is possible, under certain conditions, to perform implants with a tilt angle=0°. Despite that Si(001) is normally tilted at 7° for ion implantation (to prevent the channeling), our results demonstrated that under certain conditions (implantation through a thick dioxide), it is possible to implant phosphorus with a tilt angle=0° obtaining a poor ion channeling. This is an important technological result since it could lea