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Monday 19 March 2018, 10:00am to 11:00am
Epitaxial Growth of III-V Semiconductors on Si
III-V semiconductor materials such as InAs, AlSb, GaSb and their respective alloys offer a wide variety of band gaps and band alignments that can be used to produce numerous high performance optoelectronic devices operating in the technologically important mid-infrared (MIR) spectral range. Structures made of these materials are usually grown on wafers like GaSb and InAs, which have high cost, a non-optimized surface oxide layer, poor thermal conductivity and are only available in small sizes. The integration of III-V semiconductors on Si wafers would be most desirable to enable cost effective manufacture and open new applications in lab-on chip MIR photonic integrated circuits. However, this is a difficult task due to the large differences between the lattice constants (13%) and the thermal expansion coefficients which can lead to the formation of threading dislocations and micro fractures, and the presence of antiphase boundaries domains (APDs) owing to the polar/nonpolar character of the III-V/Si interface. During my presentation, I will talk about the molecular beam epitaxial (MBE) growth of high quality APD-free GaSb buffer layer onto Si and the resultant performance of Sb-based multilayer structures. A thin AlSb nucleation layer was also grown prior to the GaSb buffer layer, to relieve the large lattice mismatch via a periodic, self-ordered network of 90° edge dislocations which predominately propagate laterally rather than vertically into the overlying epilayer.
Engineering Department, Lancaster University
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