Interface engineering between metal electrode and GeO2 dielectric for future Ge-based metal-oxide-semiconductor technologies

Interfacial reactions between a metal-gate electrode and GeO2 dielectric in Ge-based metal-oxide-semiconductor (MOS) devices have been investigated by several analytical techniques, and we have demonstrated a method to suppress the interfacial reactions. Although no reaction occurs at the Au/GeO2 interface, a significant reaction was observed at the Al/GeO2 interface, which leads to increases in the leakage current and defect states in an MOS capacitor. While Al is oxidized at the Al/GeO2 interface, GeO2 is reduced to form Ge-Ge and Ge-Al bonding units during the early stage of the Al deposition. Moreover, the Ge-Al alloy segregates to the Al-electrode surface during the sequent Al deposition. These interfacial reactions are dramatically suppressed by insertion of ultrathin Al2O3 into the Al/GeO2 interface.

[1]  K. Nagashio,et al.  Ge/GeO2 Interface Control with High-Pressure Oxidation for Improving Electrical Characteristics , 2009, ECS Transactions.

[2]  S. Higashi,et al.  X-ray Photoelectron Spectroscopy Study of Interfacial Reactions between Metal and Ultrathin Ge Oxide , 2011 .

[3]  Heiji Watanabe,et al.  Insight into unusual impurity absorbability of GeO(2) in GeO(2)∕Ge stacks. , 2011, Applied physics letters.

[4]  Mitsuru Takenaka,et al.  Al2O3/GeOx/Ge gate stacks with low interface trap density fabricated by electron cyclotron resonance plasma postoxidation , 2011 .

[5]  Xin-Mingm Zhang,et al.  Element segregation on the surfaces of pure aluminum foils , 2010 .

[6]  Heiji Watanabe,et al.  Germanium oxynitride gate dielectrics formed by plasma nitridation of ultrathin thermal oxides on Ge(100) , 2009 .

[7]  Heiji Watanabe,et al.  Origin of flatband voltage shift and unusual minority carrier generation in thermally grown GeO2/Ge metal-oxide-semiconductor devices , 2009 .

[8]  Heiji Watanabe,et al.  First-principles study to obtain evidence of low interface defect density at Ge/GeO2 interfaces , 2009, 0904.2474.

[9]  G. Pourtois,et al.  Ge dangling bonds at the (100)Ge/GeO2 interface and the viscoelastic properties of GeO2 , 2008 .

[10]  Mitsuru Takenaka,et al.  Evidence of low interface trap density in GeO2∕Ge metal-oxide-semiconductor structures fabricated by thermal oxidation , 2008 .

[11]  Tomonori Nishimura,et al.  Direct Evidence of GeO Volatilization from GeO2/Ge and Impact of Its Suppression on GeO2/Ge Metal–Insulator–Semiconductor Characteristics , 2008 .

[12]  P. Midgley,et al.  TEM characterization of Ge precipitates in an Al-1.6at% Ge alloy. , 2008, Ultramicroscopy.

[13]  K. Saraswat,et al.  Germanium MOS capacitors incorporating ultrathin high-/spl kappa/ gate dielectric , 2002, IEEE Electron Device Letters.

[14]  Pascal Masson,et al.  Frequency characterization and modeling of interface traps in HfSixOy/HfO2 gate dielectric stack from a capacitance point-of-view , 2002 .

[15]  Dimitri A. Antoniadis,et al.  Strained Ge channel p-type metal–oxide–semiconductor field-effect transistors grown on Si1−xGex/Si virtual substrates , 2001 .

[16]  F. Maeda,et al.  Thermal decomposition pathway of Ge and Si oxides: observation of a distinct difference , 2000 .

[17]  I. Tashlykova-Bushkevich,et al.  Dope depth distribution in rapidly solidified Al–Ge and Al–Me (Me=Fe, Cu, Sb) alloys , 2000 .

[18]  Reuter,et al.  Surfactants in epitaxial growth. , 1989, Physical review letters.