Localized degradation studies of ultrathin gate oxides

We present studies on the limits of oxide reliability on a local, microscopic scale, using scanning tunneling microscope (STM)-based ballistic electron emission microscopy/spectroscopy (BEEM/S). In these studies, electrons are injected from the STM tip into the conduction band of a SiO2 layer that is imbedded in a metal–oxide–semiconductor (MOS) structure. The electron energy is determined both by the tip bias that can be set up to −13 V and by the applied oxide bias. Combining the two biases can heat electrons to energies that are unreachable in thin oxides by conventional Fowler–Nordheim injection methods. Our studies indicate that breakdowns are difficult to achieve for 7.1 nm oxides. A local breakdown was not observed even for an injected charge dosage of 1.8×103 C/cm2 at equivalent Fowler–Nordheim stress fields of ∼25 MV/cm, although defect densities in the oxide were as high as ∼5×1013/cm2. Evidence of anode hole injection is also observed under high oxide biases ∼8 MV/cm. Therefore we conclude that...

[1]  C. Hu,et al.  Hole injection SiO/sub 2/ breakdown model for very low voltage lifetime extrapolation , 1994 .

[2]  Ludeke,et al.  Structural and electronic properties of the Bi/GaP(110) interface. , 1991, Physical review. B, Condensed matter.

[3]  Kirtley,et al.  Theory of high-field electron transport in silicon dioxide. , 1985, Physical review. B, Condensed matter.

[4]  James H. Stathis,et al.  EXPLANATION FOR THE OXIDE THICKNESS DEPENDENCE OF BREAKDOWN CHARACTERISTICS OF METAL-OXIDE-SEMICONDUCTOR STRUCTURES , 1997 .

[5]  H. J. Wen,et al.  Investigation of existing defects and defect generation in device-grade SiO2 by ballistic electron emission spectroscopy , 1997 .

[6]  Eduard A. Cartier,et al.  Hot-electron dynamics in SiO 2 and the degradation of the Si/SiO 2 -interface , 1993 .

[7]  Arnold,et al.  Acoustic-phonon runaway and impact ionization by hot electrons in silicon dioxide. , 1992, Physical review. B, Condensed matter.

[8]  T. C. McGill,et al.  Macroscopic and microscopic studies of electrical properties of very thin silicon dioxide subject to electrical stress , 1997 .

[9]  Eduard A. Cartier,et al.  Impact ionization and positive charge formation in silicon dioxide films on silicon , 1992 .

[10]  H. J. Wen,et al.  Localized electron trapping and trap distributions in SiO2 gate oxides , 1997 .

[11]  K. R. Farmer,et al.  Defect instability in ultra-thin oxides on silicon , 1997 .

[12]  Arnold,et al.  Theory of high-field electron transport and impact ionization in silicon dioxide. , 1994, Physical review. B, Condensed matter.

[13]  B. Kaczer,et al.  Ballistic‐electron emission microscopy studies of charge trapping in SiO2 , 1996 .

[14]  Thomas N. Theis,et al.  Electron heating in silicon dioxide and off‐stoichiometric silicon dioxide films , 1985 .

[15]  Yuan Taur,et al.  Defect generation in 3.5 nm silicon dioxide films , 1994 .

[16]  James H. Stathis,et al.  On the relationship between stress induced leakage currents and catastrophic breakdown in ultra-thin SiO2 based dielectrics , 1997 .

[17]  E. Cartier,et al.  Stressing and high field transport studies on device‐grade SiO2 by ballistic electron emission spectroscopy , 1996 .

[18]  James Stasiak,et al.  Trap creation in silicon dioxide produced by hot electrons , 1989 .

[19]  E. Cartier,et al.  Hot electron transport through metal–oxide–semiconductor structures studied by ballistic electron emission spectroscopy , 1995 .

[20]  Douglas A. Buchanan,et al.  Reliability and integration of ultra-thin gate dielectrics for advanced CMOS , 1997 .

[21]  Douglas A. Buchanan,et al.  Hot-electron-induced hydrogen redistribution and defect generation in metal-oxide-semiconductor capacitors , 1994 .

[22]  Yuan Taur,et al.  CMOS scaling into the 21st century: 0.1 µm and beyond , 1995, IBM J. Res. Dev..

[23]  D. Newns,et al.  Image force effects and the dielectric response of SiO2 in electron transport across metal–oxide–semiconductor structures , 1997 .

[24]  H. Iwai,et al.  1.5 nm direct-tunneling gate oxide Si MOSFET's , 1996 .

[25]  Eduard A. Cartier,et al.  Anode hole injection and trapping in silicon dioxide , 1996 .