CMOS technology has been proven as one of the most important achievements in modern engineering history. In less than 30 years, it has become the primary engine driving the world economy. Device scaling makes this possible. For decades, progress in device scaling has followed an exponential curve: this has come to be known as Moore's law. Downscaling such devices like MOSFETs to their limiting sizes is a key challenge of the semiconductor industry now. Therefore device simulation requires new theory and modeling techniques, what helps to improve the understanding of device physics and design, for structures at the sub-100 nm scale, and complements experimental work in addressing this challenge. We present a new approach, which allows us to make predictions about performance of future MOSFETs. The quantum-mechanical features of the electron transport are extracted from the numerical solution of the quantum Liouville equation in the Wigner function representation.