Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics

We report the modification and control of threshold voltage in enhancement and depletion mode AlGaN/GaN metal-insulator-semiconductor heterostructure field effect transistors through the use of in-situ fluorine doping of atomic layer deposition Al2O3. Uniform distribution of F ions throughout the oxide thickness are achievable, with a doping level of up to 5.5 × 1019 cm−3 as quantified by secondary ion mass spectrometry. This fluorine doping level reduces capacitive hysteretic effects when exploited in GaN metal-oxide-semiconductor capacitors. The fluorine doping and forming gas anneal also induces an average positive threshold voltage shift of between 0.75 and 1.36 V in both enhancement mode and depletion mode GaN-based transistors compared with the undoped gate oxide via a reduction of positive fixed charge in the gate oxide from +4.67 × 1012 cm−2 to −6.60 × 1012 cm−2. The application of this process in GaN based power transistors advances the realisation of normally off, high power, high speed devices.

[1]  P. McIntyre,et al.  New method for determining flat-band voltage in high mobility semiconductors , 2013 .

[2]  P. Asbeck,et al.  Characterization of interface and border traps in ALD Al2O3/GaN MOS capacitors with two-step surface pretreatments on Ga-polar GaN , 2014 .

[3]  C. Ai,et al.  Fluorine effects on the dipole structures of the Al2O3 thin films and characterization by spectroscopic ellipsometry , 2007 .

[4]  Kevin J. Chen,et al.  High RF Performance Enhancement-Mode Al2O3/AlGaN/GaN MIS-HEMTs Fabricated With High-Temperature Gate-Recess Technique , 2015, IEEE Electron Device Letters.

[5]  Wang Chong,et al.  Breakdown voltage and current collapse of F-plasma treated AlGaN/GaN HEMTs , 2014 .

[6]  Li Yuan,et al.  Diffusion mechanism and the thermal stability of fluorine ions in GaN after ion implantation , 2009 .

[7]  Yugang Zhou,et al.  Control of Threshold Voltage of AlGaN/GaN HEMTs by Fluoride-Based Plasma Treatment: From Depletion Mode to Enhancement Mode , 2006, IEEE Transactions on Electron Devices.

[8]  G. Meneghesso,et al.  Anomalous Kink Effect in GaN High Electron Mobility Transistors , 2009, IEEE Electron Device Letters.

[9]  Xingzhao Liu,et al.  Fabrication of Enhancement-Mode AlGaN/GaN MISHEMTs by Using Fluorinated $ \hbox{Al}_{2}\hbox{O}_{3}$ as Gate Dielectrics , 2011, IEEE Electron Device Letters.

[10]  S. H. Wemple,et al.  Oxygen‐Octahedra Ferroelectrics. I. Theory of Electro‐optical and Nonlinear optical Effects , 1969 .

[11]  V. Aimez,et al.  Optimized Pre-Treatment Process for MOS-GaN Devices Passivation , 2014, IEEE Electron Device Letters.

[12]  K. B. Lee,et al.  Enhancement-mode metal–insulator–semiconductor GaN/AlInN/GaN heterostructure field-effect transistors on Si with a threshold voltage of +3.0 V and blocking voltage above 1000 V , 2015 .

[13]  C. Jaing,et al.  Optical and mechanical properties of AlF3 films produced by pulse magnetron sputtering of Al targets with CF4/O2 gas , 2009 .

[14]  Giovanni Ghione,et al.  Guest Editorial Special Issue on GaN Electronic Devices , 2013 .

[15]  Tomas Palacios,et al.  Threshold voltage control by gate oxide thickness in fluorinated GaN metal-oxide-semiconductor high-electron-mobility transistors , 2013 .

[16]  Sima Dimitrijev,et al.  Power-switching applications beyond silicon: Status and future prospects of SiC and GaN devices , 2015 .

[17]  Electron trapping in metal-insulator-semiconductor structures on n-GaN with SiO2 and Si3N4 dielectrics , 2004 .

[18]  Sam-Dong Kim,et al.  Effects of post-annealing on the passivation interface characteristics of AlGaN/GaN high electron mobility transistors , 2015 .

[19]  C. Steinbrüchel,et al.  Metal/fluorinated-dielectric interactions in microelectronic interconnections: Rapid diffusion of fluorine through aluminum , 1999 .

[20]  Hongwei Chen,et al.  Effects of the fluorine plasma treatment on the surface potential and Schottky barrier height of AlxGa1−xN/GaN heterostructures , 2010 .

[21]  S. George,et al.  Low-Temperature Al2O3 Atomic Layer Deposition , 2004 .

[22]  K. Lau,et al.  MOVPE growth of in situ SiNx/AlN/GaN MISHEMTs with low leakage current and high on/off current ratio , 2015 .

[23]  High-frequency capacitance–voltage measurement of plasma-enhanced chemical-vapor-deposition-grown SiO2/n-GaN metal-insulator-semiconductor structures , 2001 .

[24]  Umesh K. Mishra,et al.  Lateral and Vertical Transistors Using the AlGaN/GaN Heterostructure , 2013, IEEE Transactions on Electron Devices.

[25]  Robert D. Shannon,et al.  Refractive Index and Dispersion of Fluorides and Oxides , 2002 .