Matthias Bauer

Kinetics of Si incorporation into a Ge matrix for Si1−xGex layers grown by chemical vapor deposition

The growth rate and alloy composition of Si1−xGex layers grown in an industrial chemical vapor deposition (CVD) system have been analyzed as functions of the process parameters at a pressure enabling selective epitaxial growth. We systematically investigate the growth of Si1−xGex with 0.48<x<0.8, using GeH4∕SiCl2H2 partial pressure ratios up to 1.12, where the GeH4 flow was constant and the SiCl2H2 flow was varied. Epitaxial growth temperatures spanned from 350to600°C. The growth rate and alloy composition were limited by the surface reaction step with an activation energy of 1eV∕mol. A significant growth rate reduction is observed when increasing Si content. This feature is consistent with a passivation of the surface Si bonds with H and Cl atoms typical of chemical vapor deposition Si1−xGex layer growth. It is found empirically that x∕(1−x)∝pDCSΔn, Δn=0.32, where x is the Ge mole fraction and pDCS is the SiCl2H2 partial pressure. Then we tentatively develop a model to support the empirical laws found wi...

P-Channel I-MOS Transistor featuring Silicon Nano-Wire with Multiple-Gates, Strained Si 1-y C y I-region, in situ doped Si 1-y C y Source, and Sub-5 mV/decade Subthreshold Swing

We realized Impact Ionization Nanowire Multiple-gate Field- Effect Transistors (I-MuGFETs or I-FinFETs) having a multiple- gate/nanowire-channel architecture to exploit the superior gate-to- channel coupling for reduced breakdown voltage VBD and enhanced device performance. The first p-channel Impact Ionization MOS transistor (I-MOS) having in situ doped source was also demonstrated. An in situ phosphorus-doped Si source with improved dopant activation and very abrupt junction profile reduces VBD and enhances the on-state current Ion. A further improvement was also made by incorporating strained Si1-yCy impact-ionization region (I-region) and in situ doped Si1-yCy source, leading to further reduction in VBD and enhancement in Ion. This is due to strain- induced reduction of the impact-ionization threshold energy Eth. In addition, excellent subthreshold swing of below 5 mV/decade at room temperature was achieved for all devices.

Efficient Si3H8 Based Deposition Process Suitable for High Throughput Cl2 Based SiCP/SiP Cyclic Deposition and Etch Processes

In this paper, an efficient Si3H8, (SiH3CH3, and PH3) based deposition process that can be combined with a Cl2 based selective chemical vapor etch process is demonstrated . Various options for Cl2 based SiCP/SiP processes have been discussed and demonstrated. The most efficient processes are isothermal and isobaric, since temperature or pressure changes add processing time, introduce complexity and potential instabilities. Therefore, in order to maximize process efficiency and stability, the aim is to compose isothermal and isobaric process recipes. Despite the low processing temperature, high growth rates are obtained. Low processing temperature and high growth rate allow high [C] and [P] concentrations. It has been shown that periodic etching as applied in a CDE process does substantially enhance epitaxial layer quality.

Strained FinFETs with In-situ Doped Si 1-y C y Source and Drain Stressors: Performance Boost with Lateral Stressor Encroachment and High Substitutional Carbon Content

In this paper, we report the first demonstration of n-channel FinFETs with in-situ doped silicon-carbon (Si1-yCy or SiC:P) source and drain (S/D) stressors. New key features incorporated in this work for performance enhancement includes record-high substitutional carbon concentration Csub of 2.1%, high in-situ phosphorus doping concentration in S/D, extended Pi -shaped S/D stressors that wrap around the Si fin for maximum lattice interaction, lateral stressor encroachment under the spacer for closer promixity to channel region for maximum channel stress as well as reduced S/D extension resistances.