A plasma process for ultrafast deposition of SiGe graded buffer layers

Abstract

Low energy plasma enhanced chemical vapor deposition (LEPECVD) has been applied to the synthesis of Si-modulation doped field effect transistor structures, comprising a SiGe relaxed buffer layer and a modulation doped strained Si channel. A growth rate of at least 5 nm/s for the relaxed SiGe buffer layer is well above that obtainable by any other technique. Due to the low ion energies involved in LEPECVD, ion damage is absent, despite a huge plasma density. The structural quality of the LEPECVD grown SiGe buffer layers is comparable to that of state-of-the-art material. The electronic properties of the material were evaluated by growing modulation doped Si quantum wells on the buffer layers. We obtain a low temperature (2 K) Hall mobility of μH=2.5×104 cm2/Vs for the electrons in the Si channel at an electron sheet density of ns=8.6×1011 cm−2.

Electrical and structural properties of p ‐type nanocrystalline silicon grown by LEPECVD for photovoltaic applications

“…LEPECVD has already demonstrated growth rates of up to 5-10 nm/s [2] depositing high-quality epitaxial Si films using a low-voltage, high-current dc arc discharge. Due to low ion energies, a high plasma density can be magnetically confined on the substrate surface without inducing defects in the deposited film.…”

“…In this framework, low-energy plasma-enhanced chemical vapor deposition (LEPECVD) [2], like HWCVD (Hot Wire CVD) and VHF (Very High Frequency)-PECVD, is one of the new techniques developed for growing nc-Si:H at high enough deposition rates to address one of the most important obstacles towards its industrial application: the long deposition time required by standard rf-PECVD.…”

Continuum modelling of semiconductor heteroepitaxy: an applied perspective

“…For instance, 3D islanding following Ge deposition on Si(001) can be suppressed by growing outof-equilibrium. High deposition rates, and/or low deposition temperatures (as an alternative to surfactants), indeed, lead to fast film thicknening without allowing for the formation of islands [35][36][37]. In such a metastable state, the system relaxes by injecting dislocations suppressing further islanding as the effective lattice mismatch is reduced.…”

Si/SiGe Bound-to-Continuum Quantum Cascade Emitters

“…The wafers were grown by low energy plasma enhanced chemical vapour deposition (LEPECVD) (17) which has the advantage of high growth rates making the technique ideal for the thick heterostructures required for QCLs as well as microelectronic (18) Both transmission electron microscopy (TEM) and X-ray diffraction has been used to characterize the heterolayers in the deposited wafer. Samples were taken from the centre of the wafer.…”