Measurement of external stress on bulk GaN

Abstract

We report on the measurement of stress in bulk, free‐standing GaN templates under external bending using micro‐Raman scattering. A 488 nm Ar‐ion laser beam was scanned in a cross‐sectional geometry across the GaN template held under external stress conditions. Our experiment showed that the top half of the bulk GaN was under ∼73 MPa of tensile stress while the bottom half of the GaN template was under 40 MPa of compressive stress when bent by a press screw. This data is very helpful to understand both the optical and mechanical properties of bulk GaN and for calibrating and optimizing GaN‐based pressure sensors. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Characterization of erbium chloride seeded gallium nitride nanocrystals

“…2a, distinct GaN E 2 (High), E 1 (TO) and A 1 (TO) phonons are observable. This data indicates that the GaN nanocrystals have a structural quality similar to that obtained from a high quality freestanding GaN wafer [21]. No characteristic GaN peak was measured when the laser was positioned off the GaN nanocrystal in Fig.…”

Residual Stress Characterization in Microelectronic Manufacturing: An Analysis Based on Raman Spectroscopy

“…Reproduced with permission. [98] Copyright 2006, John Wiley and Sons. Addressing the influences of external damage on stress distribution, Tomar et al [93] investigated the impact of ion irradiation and corrosion on SiC stress distribution.…”

“…Consequently, measuring and analyzing residual stress in GaN materials has garnered increasing interest. In 2006, Kim et al [ 98 ] researched the Raman spectrum of bulk GaN material under external bending stress conditions, as shown in Figure a. Their results tensile stress of ≈73 MPa (red‐shift, Δω is −0.45 cm −1 ) at the top of the bulk GaN template and compressive stress of ≈40 MPa, (blue‐shift, Δω is 0.25 cm −1 ) at the bottom, as shown in Figure 12b–d.…”

“…a) Schematic of the device for applying external strain, position to be measured, and direction of stress during bending. Raman shift at Position b) A, c) B, and d) C with/without external strain.Reproduced with permission [98]. Copyright 2006, John Wiley and Sons.…”