Effect of surface passivation process for AlGaN/GaN HEMT heterostructures using phenol functionalized-porphyrin based organic molecules
Type
ArticleAuthors
Garg, Manjari
Naik, Tejas Rajendra
Pathak, Ravi
Rao, Valipe Ramgopal
Liao, Che-Hao
Li, Kuang-Hui
Sun, Haiding

Li, Xiaohang

Singh, Rajendra
KAUST Department
Advanced Semiconductor LaboratoryComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
KAUST Grant Number
BAS/1/1664-01-01URF/1/3437-01-01
REP/1/3189-01-01
Date
2018-11-19Online Publication Date
2018-11-19Print Publication Date
2018-11-21Permanent link to this record
http://hdl.handle.net/10754/630185
Metadata
Show full item recordAbstract
In this work, we investigate an unexplored possibility of passivating the charged surface states on AlGaN/GaN high electron mobility transistor (HEMT) heterostructures by using organic molecules. This has further led to remarkable enhancement in the electrical properties of rectifying metal-semiconductor contacts on AlGaN/GaN. Phenol functionalized Zinc metallated-Tetra Phenyl Porphyrin (Zn-TPPOH) organic molecules were adsorbed on AlGaN/GaN via the solution phase to form a molecular layer (MoL). The presence of the MoL was confirmed using X-ray Photoelectron Spectroscopy (XPS). The thickness of the MoL was assessed as ∼1 nm, using Spectroscopic Ellipsometry and cross-sectional Transmission Electron Microscopy. XPS peak-shift analyses together with Kelvin Probe Force Microscopy revealed that the molecular surface modification reduced the surface potential of AlGaN by approximately 250 meV. Consequently, the Barrier height (ideality factor) of Ni Schottky diodes on AlGaN/GaN was increased (reduced) significantly from 0.91 ± 0.05 eV (2.5 ± 0.31) for Ni/AlGaN/GaN to 1.37 ± 0.03 eV (1.4 ± 0.29) for Ni/Zn-TPPOH/AlGaN/GaN. In addition, a noteworthy decrement in the reverse current from 2.6 ± 1.93 μA to 0.31 ± 0.19 nA at −5 V (∼10 000 times) was observed from Current-Voltage (I-V) measurements. This surface-modification process can be fruitful for improving the performance of AlGaN/GaN HEMTs, mitigating the adverse effects of surface states and polarization in these materials.Citation
Garg M, Naik TR, Pathak R, Rao VR, Liao C-H, et al. (2018) Effect of surface passivation process for AlGaN/GaN HEMT heterostructures using phenol functionalized-porphyrin based organic molecules. Journal of Applied Physics 124: 195702. Available: http://dx.doi.org/10.1063/1.5049873.Sponsors
Manjari Garg is grateful to the Council of Scientific and Industrial Research (CSIR), India, for providing research fellowship. The authors would like to acknowledge Indian Nanoelectronics User Program (INUP) at Indian Institute of Technology Bombay for the molecular chemisorption work and XPS measurements. The authors are also thankful to Professor M. Ravikanth, IIT Bombay, for porphyrin based organic molecules. The authors are also obliged to Nanoscale Research Facility (NRF) at Indian Institute of Technology Delhi for the deposition of Cu and Ni Schottky contacts and for KPFM, Spectroscopic Ellipsometry, and I-V and C-V measurements. The KAUST authors acknowledge the support from KAUST Baseline BAS/1/1664-01-01, KAUST Competitive Research Grant URF/1/3437-01-01, and GCC Grant REP/1/3189-01-01.Publisher
AIP PublishingJournal
Journal of Applied PhysicsAdditional Links
https://aip.scitation.org/doi/10.1063/1.5049873ae974a485f413a2113503eed53cd6c53
10.1063/1.5049873