Recent results on AlN growth by HVPE and fabrication of free standing AlN wafers

Abstract

Abstract Properties of thick crack‐free AlN layers grown by hydride vapor phase epitaxy (HVPE) on 2‐inch and 3‐inch silicon carbide (SiC) and sapphire substrates are described. The maximum thickness of crack free layer was 75 μm and 15 μm for AlN grown on SiC and sapphire, respectively. Wafer bow was contolled below 50 μm for AlN/SiC wafers. Surface for as‐grown and polished AlN surface was studied. X‐ray diffraction and wet chemical etching was used for crystal quality evaluation showing defect density in high 10 7 to low 10 8 cm –2 range. Initial experiments on AlN growth on patterened SiC wafers resulted in local etch pit density of about 2x10 7 cm –2 for 35 μm thick AlN layer. Electrical resistivity of AlN layers exceeded 10 11 and 10 6 Ω cm at 300 K and 600 K, respectively. Free‐standing 2‐inch AlN wafers were fabricated by removal of SiC substrate using reactive ion etching. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)