Smooth GaN membranes by polarization-assisted electrochemical etching
Artikel i vetenskaplig tidskrift, 2021

III-nitride membranes offer promising perspectives and improved device designs in photonics, electronics, and optomechanics. However, the removal of the growth substrate often leads to a rough membrane surface, which increases scattering losses in optical devices. In this work, we demonstrate membranes with etched surface roughness comparable to that of the as-grown epitaxial material, accomplished by the implementation of a properly designed built-in polarization field near the top of the sacrificial layer from an AlInN interlayer, which is polarization-mismatched to GaN. This leads to a steeper reduction in free carrier density during the electrochemical etching of the sacrificial layer, limiting the etching current and thus causing an abrupter etch stop. As a result, the root mean square roughness is reduced to 0.4nm over 5x5 mu m(2). These smooth membranes open attractive pathways for the fabrication of high-quality optical cavities and waveguides operating in the ultraviolet and visible spectral regions.

Författare

Joachim Ciers

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Michael Alexander Bergmann

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Filip Hjort

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

J-F Carlin

Ecole Polytechnique Federale de Lausanne (EPFL)

N. Grandjean

Ecole Polytechnique Federale de Lausanne (EPFL)

Åsa Haglund

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Applied Physics Letters

0003-6951 (ISSN) 1077-3118 (eISSN)

Vol. 118 6 062107

Ämneskategorier

Atom- och molekylfysik och optik

Annan fysik

Den kondenserade materiens fysik

DOI

10.1063/5.0034898

Mer information

Senast uppdaterat

2021-04-06