The control of mechanical bow for GaN substrate grown by HVPE with relatively longer radius of lattice curvature

Abstract

AbstractWe are going to develop GaN growth process by HVPE method, which shows the near null value of free standing (FS)‐GaN wafer bowing after laser lift‐off (LLO) process in order to reduce the production cost of GaN substrate. The 309 to 318 µm thick HVPE grown GaN layers on sapphire shows 574 to 669 µm of as grown bows, and –299 to 95 µm of bow after LLO process. The 440 µm thick HVPE grown GaN layer on sapphire shows 693 µm of as grown bow, and –4 µm of bow after LLO process. From this GaN template, we could get the 356 µm thick FS‐GaN wafer with 2 µm of bow after polishing. This GaN substrate shows at least 43.87 m of the radius of lattice curvature evaluated by 9‐points measuring of (004) rocking curve along center line parallel to the main flat plane. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)