title: Mechanical properties of nanoporous GaN and its application for separation and transfer of GaN thin films.
abstract: Nanoporous (NP) gallium nitride (GaN) as a new class of GaN material has many interesting properties that the conventional GaN material does not have. In this paper, we focus on the mechanical properties of NP GaN, and the detailed physical mechanism of porous GaN in the application of liftoff. A decrease in elastic modulus and hardness was identified in NP GaN compared to the conventional GaN film. The promising application of NP GaN as release layers in the mechanical liftoff of GaN thin films and devices was systematically studied. A phase diagram was generated to correlate the initial NP GaN profiles with the as-overgrown morphologies of the NP structures. The fracture toughness of the NP GaN release layer was studied in terms of the voided-space-ratio. It is shown that the transformed morphologies and fracture toughness of the NP GaN layer after overgrowth strongly depends on the initial porosity of NP GaN templates. The mechanical separation and transfer of a GaN film over a 2 in. wafer was demonstrated, which proves that this technique is useful in practical applications.
authors.affiliation: Department of Electrical Engineering, Yale University , New Haven, Connecticut 06520, United States .
authors.forename: Shanjin
authors.initials: S
authors.lastname: Huang
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Benjamin
authors.initials: B
authors.lastname: Leung
authors.forename: Ge
authors.initials: G
authors.lastname: Yuan
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Jiang
authors.forename: Yingmin
authors.initials: Y
authors.lastname: Fan
authors.forename: Qian
authors.initials: Q
authors.lastname: Sun
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Wang
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Jung
authors.initials: J
authors.lastname: Han
mesh_terms: D055119:Elastic Modulus; D005708:Gallium / Q000737:chemistry*; D055595:Mechanical Phenomena; D058608:Nanopores / Q000648:ultrastructure*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D013499:Surface Properties
chemical_list: C473348:gallium nitride; D005708:Gallium