Surface passivation of GaN and GaN/AlGaN heterostructures by dielectric films and its application to insulated-gate heterostructure transistors

We have systematically investigated effects of plasma processing, formation of Si-based dielectrics, and formation of a thin Al2O3 film on the chemical and electronic properties of GaN and GaN/AlGaN heterostructure surfaces. The surface treatment in H2-plasma excited by electron-cyclotron-resonance (ECR) source, produced nitrogen-vacancy-related defect levels at GaN and AlGaN surfaces, while the ECR-N2-plasma treatment improved electronic properties of the surfaces. The deposition of a SiO2 film on GaN and AlGaN surfaces was found to induce high-density interface states, due to unexpected and uncontrollable oxidation reactions on the surfaces during the deposition process. In comparison, the SiNx/GaN passivation structure prepared by ECR-plasma assisted chemical vapor deposition showed good interface properties with the minimum Dit value of 1×1011 cm−2 eV−1. However, excess leakage currents governed by Fowler–Nordheim tunneling were observed in the SiNx/Al0.3Ga0.7N structure, due to a relatively small con...

[1]  Tso-Ping Ma,et al.  High-quality oxide/nitride/oxide gate insulator for GaN MIS structures , 2001 .

[2]  Laser-assisted nitridation of GaAs: mechanisms , 1993 .

[3]  Van de Walle CG,et al.  Atomic geometry and electronic structure of native defects in GaN. , 1994, Physical review. B, Condensed matter.

[4]  R. Davis,et al.  Dependence of (0001) GaN/AlN valence band discontinuity on growth temperature and surface reconstruction , 1998 .

[5]  Hideki Hasegawa,et al.  Insulator-GaN interface structures formed by plasma-assisted chemical vapor deposition , 2000 .

[6]  Rishabh Mehandru,et al.  Influence of MgO and Sc2O3 passivation on AlGaN/GaN high-electron-mobility transistors , 2002 .

[7]  A. Roskowski,et al.  Pd growth and subsequent Schottky barrier formation on chemical vapor cleaned p-type GaN surfaces , 2002 .

[8]  S. Imanaga,et al.  Current–Voltage Characteristics of AlN/GaN Heterostructure Metal Insulator Semiconductor Diode , 2001 .

[9]  K. Kasahara,et al.  Microwave Performance of 0.3-µm Gate-Length Multi-Finger AlGaN/GaN Heterojunction FETs with Minimized Current Collapse , 2000 .

[10]  S. Mohney,et al.  Environmental aging of Schottky contacts to n-AlGaN , 2001 .

[11]  L. Eastman,et al.  The effect of surface passivation on the microwave characteristics of undoped AlGaN/GaN HEMTs , 2000, IEEE Electron Device Letters.

[12]  T. Hashizume,et al.  X-ray photoelectron spectroscopy characterization of AlGaN surfaces exposed to air and treated in NH4OH solution , 2000 .

[13]  Seiichi Miyazaki,et al.  Photoemission study of energy-band alignments and gap-state density distributions for high-k gate dielectrics , 2001 .

[14]  Hideki Hasegawa,et al.  Chemistry and electrical properties of surfaces of GaN and GaN/AlGaN heterostructures , 2001 .

[15]  Yutaka Ohno,et al.  Current Collapse in AlGaN/GaN HEMTs Investigated by Electrical and Optical Characterizations , 2002 .

[16]  U. Mishra,et al.  The impact of surface states on the DC and RF characteristics of AlGaN/GaN HFETs , 2001 .

[17]  Edward T. Yu,et al.  Gate leakage current mechanisms in AlGaN/GaN heterostructure field-effect transistors , 2000 .

[18]  J. Chyi,et al.  Properties of Ga2O3(Gd2O3)/GaN metal–insulator–semiconductor diodes , 2000 .

[19]  Michael S. Shur,et al.  Si3N4/AlGaN/GaN–metal–insulator–semiconductor heterostructure field–effect transistors , 2001 .

[20]  S. Imanaga,et al.  AlN/GaN insulated gate heterostructure FET with regrown n+GaN ohmic contact , 1998 .

[21]  G. Lucovsky,et al.  Charge redistribution at GaN–Ga2O3 interfaces: a microscopic mechanism for low defect density interfaces in remote-plasma-processed MOS devices prepared on polar GaN faces , 2000 .

[22]  Hideki Hasegawa,et al.  Mechanism of anomalous current transport in n-type GaN Schottky contacts , 2002 .

[23]  J. Waldrop,et al.  Measurement of AlN/GaN (0001) heterojunction band offsets by x‐ray photoemission spectroscopy , 1996 .

[24]  Michael S. Shur,et al.  AlGaN/GaN metal–oxide–semiconductor heterostructure field-effect transistors on SiC substrates , 2000 .

[25]  R. Sauer,et al.  Temperature dependence of the E2 and A1(LO) phonons in GaN and AlN , 1999 .

[26]  E. Yamaguchi,et al.  Effects of nitrogen vacancy on optical properties of nitride semiconductors , 1998 .

[27]  James S. Speck,et al.  Dislocation mediated surface morphology of GaN , 1999 .

[28]  Robert F. Davis,et al.  Cleaning of AlN and GaN surfaces , 1998 .

[29]  Effects of nitrogen addition on methane-based ECR plasma etching of gallium nitride , 2002 .

[30]  Briggs,et al.  Native defects in gallium nitride. , 1995, Physical review. B, Condensed matter.