Comprehensive magnetotransport characterization of two dimensional electron gas in AlGaN/GaN high electron mobility transistor structures leading to the assessment of interface roughness

• Published in: AIP advances 2014-09, Vol.4 (9), p.097124-097124-10
• Main Authors: Mishra, Manna Kumari, Sharma, Rajesh K., Manchanda, Rachna, Bag, Rajesh K., Thakur, Om Prakash, Muralidharan, Rangarajan
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitrides; DEPOSITS; DOPED MATERIALS; ELECTRON GAS; ELECTRON MOBILITY; Electrons; Epitaxial growth; GALLIUM NITRIDES; High electron mobility transistors; Interface roughness; MAGNETIC FIELDS; MAGNETORESISTANCE; Magnetoresistivity; MATERIALS SCIENCE; MOLECULAR BEAM EPITAXY; OSCILLATIONS; ROUGHNESS; SCATTERING; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE; TRANSISTORS; Transport
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.4896192

Magnetotransport in two distinct AlGaN/GaN HEMT structures grown by Molecular Beam Epitaxy (MBE) on Fe-doped templates is investigated using Shubnikov de-Haas Oscillations in the temperature range of 1.8–6 K and multicarrier fitting in the temperature range of 1.8–300 K. The temperature dependence of the two dimensional electron gas mobility is extracted from simultaneous multicarrier fitting of transverse and longitudinal resistivity as a function of magnetic field and the data is utilized to estimate contribution of interface roughness to the mobility and the corresponding transport lifetime. The quantum scattering time obtained from the analysis of Shubnikov de Haas Oscillations in transverse magnetoresistance along with the transport lifetime time were used to estimate interface roughness amplitude and lateral correlation length. The results indicate that the insertion of AlN over layer deposited prior to the growth of GaN base layer on Fe doped GaN templates for forming HEMT structures reduced the parallel conduction but resulted in an increase in interface roughness.