Growth of aluminum nitride on flat and patterned Si (111) by high temperature halide CVD

• Published in: Thin solid films 2017-02, Vol.623, p.65-71
• Main Authors: Chubarov, Mikhail, Mercier, Frederic, Lay, Sabine, Charlot, Frederic, Crisci, Alexandre, Coindeau, Stéphane, Encinas, Thierry, Ferro, Gabriel, Reboud, Roman, Boichot, Raphaël
• Format: Article
• Language: English
• Subjects: Aluminum nitride; Chemical and Process Engineering; Chemical Sciences; Engineering Sciences; Epitaxial lateral overgrowth; Halide chemical vapor deposition; High growth rate; Material chemistry; Materials; Pillar patterned substrate; Process parameters influence; Silicon substrate
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2016.11.045

The aim of the present study is to evaluate the possibility of improving crystalline quality of AlN deposited on Si (111) substrates by implementation of substrate patterning. Growth on flat Si (111) substrates was conducted to investigate influence of deposition parameters on the growth behavior and quality of resulting AlN films. This investigation showed that SiC buffer layer is required to suppress disorientation of the AlN layer, optimum growth temperature is about 1260°C, Al-rich conditions favor more rapid coalescence of the nucleation island while N-rich conditions lead to the formation of a smooth surface. Transposition of the resulting AlN growth recipe on to patterned Si (111) substrates revealed reduction of the stress in AlN, bending of the threading dislocations and formation of a dislocation free area in the overgrown region. For the formation of a continuous layer on silicon pillars, we propose a novel technique based on the decrease of the mean free path of gaseous species leading to localized growth of AlN on the top of the pillars. Such continuous layer exhibit lower crack density compared to that on a flat substrate. Thus, the growth of AlN on pillar patterned Si substrate is seen to be a promising way for the further improvement of the AlN films quality. •SiC buffer layer is necessary to suppress disorientation of AlN on Si substrate.•AlN grown on pillar-patterned Si substrate has lower stress.•Overgrown AlN exhibit lower dislocation density.•Coalesced AlN layer on patterned substrate has lower crack density.