Papers by Keyword: Strained Si

Abstract: The effect of 2-MeV electron irradiation of Si_1-xGe_x S/D p-MOSFETs with different gate length and Ge concentration is studied. After electron irradiation, the maximum hole mobility decreases with increasing electron fluence for all gate lengths. In particular, after 5 x 10¹⁷e/cm² irradiation, the maximum hole mobility drastically decreases at short channel region for x = 0.3. Furthermore, a negative shift of the threshold voltage is clearly observed. These degradations can be explained both by the lattice defects and the stress relaxation in the Si channel created by atomic displacements.

Abstract: Threshold voltage models for both buried channel and surface channel for the dual-channel strained Si/strained Si_1-xGe_x/relaxd Si_1-yGe_y(s-Si/s-SiGe/Si_1-yGe_y) p-type metal-oxide-semiconductor field-effect transistor (PMOSFET) are presented in this paper. And the maximum allowed thickness of s-Si is given, which can ensure that the strong inversion appears earlier in the buried channel (compressive strained SiGe) than in the surface channel, because the hole mobility in the buried channel is higher than that the surface channel. They offer a good accuracy as compared with the results of device simulator ISE.

Abstract: Based on Fermi's golden rule and the theory of Boltzmann collision term approximation, taking into account all the scattering mechanisms contributed by ionized impurity, acoustic phonon and intervalley phonon, the model of total scattering rate of strained Si/(100) Si1-xGex is established. Simulating of the scattering models with Matlab software, it was found that the total scattering rate of electron in strained Si/(100) Si1-xGex decreases obviously with the increasing stress when Ge fraction x is less than 0.2 and the values continue to show a constant tendency, and that the total electron scattering rate of strained Si/(100) Si1-xGex decreases about 57% at most comparison with one of unstrained Si. The result can provide valuable references to the research of electron mobility of strained Si materials and the design of NMOS devices.

Abstract: There has been much interest in the Si-based strained technology lately. The improvement of strained-Si device performance is due to the enhancement of the mobility, so the further study on mobility is essential in both theory and practice aspects. In this paper, an analytical model of the electron mobility of strained-Si material, such as biaxial tensile strained-Si material grown on relaxed Si1-xGex (0≤x≤0.6) substrates, as a function of strain and different orientations is obtained. The results show that the electron mobilities for [100] and [010] orientations increase rapidly with increasing Ge fraction x, and there is no electron mobility enhancement for [001] orientation in comparison to relaxed Si material.

Abstract: We present the linear stability analysis for the epitaxial thin film growth on the vicinal surface of strained Si and the growth mode diagrams of the epitaxial growth under various operation conditions. Competition between step-step elastic interactions and the asymmetry of incorporation of adatoms from the terraces to step edge is considered. Force monopoles at steps and their interaction lead to it on the vicinal surface while kinetic asymmetry of the adatom incorporation at steps due to Ehrlich-Schwoebel barrier prevents the step bunching instability. Growth mode on the vicinal surface is determined by the competition between elastic step-step interactions and Ehrlich-Schwoebel barrier.