Selective Epitaxy of Group IV Materials for CMOS Application

As the International Technology Roadmap for Semiconductors (ITRS) demands an increase of transistor density in the chip, the size of transistors has been continuously shrunk. In this evolution of transistor structure, different strain engineering methods were introduced to induce strain in the channel region. One of the most effective methods is applying embedded SiGe as stressor material in source and drain (S/D) regions by using selective epitaxy. This chapter presents an overview of implementation, modeling, and pattern dependency of selective epitaxy for S/D application in CMOS. The focus is also on the wafer in and ex situ cleaning prior to epitaxy, integrity of gate, and selectivity mode

Stabilization of Ge-rich defect complexes originating from E centers in Si1- xGex:P

Thermal evolution of vacancy complexes was studied in P-doped ([P]=10 exp 18 cm exp −3) proton irradiated Si1−xGex with Ge contents of 10%, 20%, and 30% in the range of 250–350 °C using positron annihilation spectroscopy. The radiation damage recovers in the course of anneals but the final state differs from that in as-grown samples indicating the presence of small Ge clusters in the samples, contrary to the initially random Ge distribution. The activation energy for the annealing process was estimated to be 1.4±0.3 eV and attributed to the dissociation energy of the vacancy-phosphorus-germanium (V-P-Ge) complex.Peer reviewe

CVD growth of high speed SiGe HBTs using SiH4, Journal of Telecommunications and Information Technology, 2000, nr 3,4

C have been investigated. The results showed that the growth rate of SiGe layers has a strong effect on the evolution of defect density in the structure. Furthermore, B-doped SiGe layers have a higher thermal stability compared to undoped layers. The analysis of the collector profiles showed a higher incorporation of P in silane-based epitaxy compared to As. Meanwhile, the growth of As- or P-doped layers on the patterned substrates suffered from a high loading effect demanding an accurate calibration

Thomas-Fermi approach to resonant tunneling in delta-doped diodes

We study resonant tunneling in B-$\delta$-doped diodes grown by Si-molecular beam epitaxy. A Thomas-Fermi approach is used to obtain the conduction-band modulation. Using a scalar Hamiltonian within the effective-mass approximation we demonstrate that the occurrence of negative differential resistance (NDR) only involves conduction-band states, whereas interband tunneling effects seem to be negligible. Our theoretical results are in very good agreement with recent experimental observations of NDR in this type of diodes.Comment: 6 pages, REVTeX 3.0, 5 figures available from [email protected]

Undoped Strained Ge Quantum Well with Ultrahigh Mobility Grown by Reduce Pressure Chemical Vapor Deposition

We fabricate an undoped Ge quantum well under 30 nm Ge0.8Si0.2 shallow barrier with reverse grading technology. The under barrier is deposited by Ge0.8Si0.2 followed by Ge0.9Si0.1 so that the variation of Ge content forms a sharp interface which can suppress the threading dislocation density penetrating into undoped Ge quantum well. And the Ge0.8Si0.2 barrier introduces enough in-plane parallel strain -0.41% in the Ge quantum well. The heterostructure field-effect transistors with a shallow buried channel get a high two-dimensional hole gas (2DHG) mobility over 2E6 cm2/Vs at a low percolation density of 2.51 E-11 cm2. We also discover a tunable fractional quantum Hall effect at high densities and high magnetic fields. This approach defines strained germanium as providing the material basis for tuning the spin-orbit coupling strength for fast and coherent quantum computation.Comment: 11 pages, 5 figure

Special Issue: Silicon Nanodevices

In recent years, nanodevices have attracted a large amount of attention due to their low power consumption and fast operation in electronics and photonics, as well as their high sensitivity in sensor applications [...

Improvement of infrared detection using Ge quantum dots multilayer structure

Monocrystalline SiGe/Si multiquantum dot and well structures have been manufactured/compared as thermistor materials for infrared detection. The performance of the devices (both the thermal and electrical) has been very sensitive to the quality of the epitaxial layers which is evaluated by the interfacial roughness and strain amount. This study demonstrates that the devices containing quantum dots have higher thermal coefficient resistance 3.4%/K with a noise constant (K1/f) value of 2× 10-9