Investigation of Structural, Optical and Electrical Properties of Al0.3Ga0.7N/GaN HEMT Grown by MOCVD

Year 2020, Volume: 23 Issue: 3, 687 - 696, 01.09.2020

Ömer Akpınar , Ahmet Kürşat Bilgili Mustafa Kemal Öztürk , Süleyman Özçelik , Ekmel Özbay

https://doi.org/10.2339/politeknik.583898

Abstract

In this study, Al_0.3Ga_0.7N/GaN
high electron mobility transistor (HEMT) structure is investigated grown over
c- oriented sapphire substrate by using Metal Organic Chemical Vapor Deposition
(MOCVD) method. Optical, morphological and electrical characteristics of this
structure are determined by X-ray diffraction (XRD), Photoluminecanse (PL),
Ultraviolet (UV-Vis.), Atomic Force Microscopy (AFM) and Hall- Resistivity
measurements. By using XRD method, 2θ, Full Width at Half Maximun (FWHM),
lattice parameters, crystallite size, strain, stress and dislocation values are
calculated on symmetric and asymmetric planes. Direct band gap of GaN is
determined by PL measurements as 3.24 eV. It is seen that conduction of AlGaN
layer starts at 360 nm in UV-Vis. In Hall-Resistivity measurements, it is
noticed that carrier density of HEMT structure is not effected by temperature
and mobility value is high. Carrier density and mobility values are determined
as 5.82x10¹⁵ 1/cm³ and 1198 cm²/Vs at room
temperature respectively. At the lowest temperature point (25 K) they are
calculated as 5.19x10¹⁵ 1/cm³ and 6579 cm²/Vs,
respectively.

Keywords

HEMT, XRD, Strain, Stress

Supporting Institution

Presidency Strategy and Budget Directorate

Project Number

2016K121220

Thanks

This work was supported by the Presidency Strategy and Budget Directorate (Grants Numbers: 2016K121220).

Investigation of Structural, Optical and Electrical Properties of Al0.3Ga0.7N/GaN HEMT Grown by MOCVD

Abstract

In this study, Al_0.3Ga_0.7N/GaN
high electron mobility transistor (HEMT) structure is investigated grown over
c- oriented sapphire substrate by using Metal Organic Chemical Vapor Deposition
(MOCVD) method. Structural, optical, morphological and electrical
characteristics of this structure are determined by X-ray diffraction (XRD), Photoluminescence (PL), Ultraviolet (UV-Vis.), Atomic Force Microscopy
(AFM) and Hall- Resistivity measurements. By using XRD method, 2θ, Full Width
at Half Maximun (FWHM), lattice parameters, crystallite size, strain, stress
and dislocation values are calculated on symmetric and asymmetric planes.
Direct band gap of GaN is determined by PL measurements as 3.24 eV. It is seen
that conduction of AlGaN layer starts at 360 nm in UV-Vis. In Hall-Resistivity
measurements, it is noticed that carrier density of HEMT structure is not
effected by temperature and mobility value is high. Carrier density and
mobility values are determined as 5.82x10¹⁵ 1/cm³ and
1198 cm²/V.s at room temperature, respectively. At the lowest temperature
point (25 K) they are calculated as 5.19x10¹⁵ 1/cm³ and
6579 cm²/Vs, respectively.

Keywords

HEMT, XRD, Hall, strain, stress

Project Number

2016K121220

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