Effectiveness of selective area growth using van der Waals h-BN layer for crack-free transfer of large-size III-N devices onto arbitrary substrates

Abstract

Selective Area van der Waals Epitaxy (SAVWE) of III-Nitride device has been proposed recently by our group as an enabling solution for h-BN-based device transfer. By using a patterned dielectric mask with openings slightly larger than device sizes, pick-and-place of discrete LEDs onto flexible substrates was achieved. A more detailed study is needed to understand the effect of this selective area growth on material quality, device performance and device transfer. Here we present a study performed on two types of LEDs (those grown on h-BN on patterned and unpatterned sapphire) from the epitaxial growth to device performance and thermal dissipation measurements before and after transfer. Millimeter-size LEDs were transferred to aluminum tape and to silicon substrates by van der Waals liquid capillary bonding. It is shown that patterned samples lead to a better material quality as well as improved electrical and optical device performances. In addition, patterned structures allowed for a much better transfer yield to silicon substrates than unpatterned structures. We demonstrate that SAVWE, combined with either transfer processes to soft or rigid substrates, offers an efficient, robust and low-cost heterogenous integration capability of large-size devices to silicon for photonic and electronic applications.

Influence of Sapphire Substrate Orientation on the van der Waals Epitaxy of III-Nitrides on 2D Hexagonal Boron Nitride: Implication for Optoelectronic Devices

“…These dislocations may originate from the AlGaN layer and can be explained by the growth mechanism of 3D layers on 2D crystals. Indeed, since the III-nitride structure is grown on the h-BN surface with no dangling bonds, these threading dislocations mostly originate from the formation of grain boundaries during the nucleation of the AlGaN layer on h-BN . For GaN/AlGaN/h-BN grown on the m- plane, the cross-sectional STEM image is completely different compared to a- and c- planes, where a terraced structure has been observed, in agreement with the SEM image.…”

Monolithic Free-Standing Large-Area Vertical III-N Light-Emitting Diode Arrays by One-Step h-BN-Based Thermomechanical Self-Lift-Off and Transfer

“…Nevertheless, the n-contact of these structures is realized on the n-AlGaN layer on h-BN which, as shown in our previous work 30 , has lower crystalline quality than the n-GaN buffer near the MQWs. Thus, strong carrier recombination process can occur at the grain boundaries of the AlGaN layer.…”

“…Helpfully, the separated surface is atomically flat allowing for an efficient transfer to rigid substrate 28 , and the native substrate can be reused repeatedly as a growth substrate. Moreover, when combined with selective area growth, we have demonstrated large surface crack-free planar LEDs transferred to arbitrary substrates 29,30 . In addition, the use of 2D hBN has three key advantages.…”

“…Helpfully, the separated surface is atomically flat allowing for an efficient transfer to a rigid substrate, and the native substrate can be reused repeatedly as a growth substrate. Moreover, when combined with selective area growth, we have demonstrated large surface crack-free planar LEDs transferred to arbitrary substrates. , In addition, the use of 2D hBN has three key advantages. First , hBN can be grown by Metal Organic Chemical Vapor Deposition (MOCVD) in the same run and under the same growth conditions as the LED structures, which is a very important characteristic.…”

Strain Balanced Self‐Supporting Single‐Crystalline LiNbO3 Thin Films for Flexible Electronics

“…[9] These methods can transfer the released epilayer onto arbitrary substrates, and realize the reuse of the expensive substrates. However, the specific substrate with lattice and thermal expansion matched to the target singlecrystalline film is generally required, [6,[10][11][12] which limits the quality and variety of the functional film. Besides, the imperfect lattice and thermal expansion matching between the epitaxial film and the supporting substrate will introduce internal strain inside the epitaxial film, [13][14][15] which may cause deformations (e.g., curling [16] or chipping [17] ) when the epitaxial film is released or transferred.…”