Abstract: Considering potential configuration of a silicon nanocrystal based memory and the mixing effect of valence bands,we calculate direct tunneling time of electron and hole with sequential tunnel theory and in the Bardeen's transfer Hamiltonian formalism.The programming and retention times of a silicon nanocrystal based memory are calculated.Influences of structure and bias on the performance of device are discussed.It is shown that new devices are expected in order to improve the retention property of silicon nanocrystal based memories.

Key words: direct tunneling, transfer Hamiltonian formalism, nanocrystals based memory