Open AccessEffect of Dry Thermal Oxidation on Bulk GaN Substrates Grown by HVPE during CMP
Author(s) -
Hyo Sang Kang,
Joohyung Lee,
Hee Ae Lee,
Jun Young Lee,
Won Il Park,
Seong Kuk Lee,
Jae Hwa Park,
Sung Chul Yi
Publication year - 2019
Publication title -
ecs journal of solid state science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.488
H-Index - 51
eISSN - 2162-8777
pISSN - 2162-8769
DOI - 10.1149/2.0221912jss
Subject(s) - materials science , x ray photoelectron spectroscopy , chemical mechanical planarization , thermal oxidation , substrate (aquarium) , surface roughness , thermal , diffusion , polishing , surface finish , chemical engineering , composite material , layer (electronics) , oceanography , physics , meteorology , engineering , thermodynamics , geology
Chemical mechanical polishing (CMP) of bulk GaN substrates via dry thermal oxidation is investigated in this paper. In this work, we study the effects of oxidation with respect to different thermal treatments, change in morphology and thickness on bulk GaN substrates. The results of the study show that a defect-free surface with roughness average (Ra) and material removal rate (MRR) of 0.377 nm and 51 μm/h respectively is achievable by CMP after thermal treatment at 800°C. However, for thermal treatments above 900°C, several pits and defects are observed with significant deformation of the surface likely due to the domination of diffusion-controlled reaction over interfacial reaction-controlled. The molar fractions of the chemical components remained on the polished GaN surfaces are characterized via X-ray photoelectron spectroscopy. It is found that the conversion rate from GaN to Ga 2 O 3 is dependent on the real contact area between CMP pad and GaN substrate surface during the CMP.