Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 4: GaN: Preparation and Characterization I (mainly Optics)
HL 4.9: Talk
Monday, March 26, 2012, 11:30–11:45, EW 201
Structural and optical quality of GaN films grown on Sc2O3/Y2O3/Si(111) — •Lidia Tarnawska1, Peter Zaumseil1, Peter Storck2, and Thomas Schroeder1 — 1IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany — 2SILTRONIC AG, Hanns-Seidel Platz 4, 81737 Munchen, Germany
Growth of GaN on Si wafers is intensively pursued to provide high quality cost effective GaN virtual substrates for electronic and optoelectronic applications. The direct deposition of GaN layers on Si is, however, a big challenge due to high reactivity of the Si surface with nitrogen, large lattice mismatch, and difference in thermal expansion coefficients. To solve the integration problems different semiconducting and insulating buffer layers were used in the past. We present a novel approach for the integration of GaN on Si(111) via Sc2O3/Y2O3 bi-layer buffer system. Samples were prepared in a multichamber molecular beam epitaxy system on 4-inch Si(111) wafers. To obtain complete information on the quality of GaN/Sc2O3/Y2O3/Si(111) heterostructures in-situ (RHEED and XPS) and ex-situ (XRD, SEM, TEM, EDX and PL) measurements were performed.Our studies show that the oxides buffer approach provides a template of high structural quality for GaN overgrowth. XRD analysis prove that the growth of single crystalline, wurzite GaN layers are achieved. The main defects in 900 nm-thick GaN layers are threading dislocations, with density in the order of 1010 cm−2, and stacking faults, resulting in cubic inclusions within the hexagonal matrix. 10K photoluminescence show a relatively sharp (FWHM of 22 meV) donor bound exciton line at 3.45 eV.