The role of border traps in MOS high-temperature postirradiation annealing response

A very-long-term study of the response of nonradiation-hardened MOS transistors to elevated-temperature, postirradiation biased anneals has been performed. The midgap-voltage shift of these devices returns to approximately 0 V during a 2.75-year, +6 V 100 degrees C anneal, supporting the idea that in these devices interface traps and border traps (near-interfacial oxide traps which can exchange charge with the underlying Si) are charge-neutral at midgap. Subsequent switched-bias annealing reveals that a significant fraction of the radiation-induced trapped holes have not been removed from the device, but are compensated by electrons in border traps. These border traps can lead to large, reversible changes in midgap-voltage shifts and/or subthreshold stretchout during switched-bias anneals. Midgap-voltage and subthreshold-stretchout reversibility remains significant in these devices even after annealing at temperatures up to 350 degrees C. Similar reversibility in postirradiation response is observed for hardened transistors and capacitors. These results suggest that border traps may lead to increased reliability problems in some irradiated devices as compared to their unirradiated counterparts. >

[1]  Dennis B. Brown,et al.  Experimental evidence of two species of radiation induced trapped positive charge , 1993 .

[2]  Daniel M. Fleetwood,et al.  Comparison of MOS capacitor and transistor postirradiation response , 1989 .

[3]  G. Groeseneken,et al.  A reliable approach to charge-pumping measurements in MOS transistors , 1984, IEEE Transactions on Electron Devices.

[4]  P. S. Winokur,et al.  Predicting CMOS Inverter Response in Nuclear and Space Environments , 1983, IEEE Transactions on Nuclear Science.

[5]  F. V. Thome,et al.  High-temperature silicon-on-insulator electronics for space nuclear power systems: requirements and feasibility , 1988 .

[6]  Daniel M. Fleetwood,et al.  1/f noise in n- and p-channel MOS devices through irradiation and annealing , 1991 .

[7]  Daniel M. Fleetwood,et al.  Theory and application of dual-transistor charge separation analysis , 1989 .

[8]  P. S. Winokur,et al.  Physical Mechanisms Contributing to Device "Rebound" , 1984, IEEE Transactions on Nuclear Science.

[9]  Patrick M. Lenahan,et al.  Hole traps and trivalent silicon centers in metal/oxide/silicon devices , 1984 .

[10]  Daniel M. Fleetwood,et al.  Effect of post-oxidation anneal temperature on radiation-induced charge trapping in metal-oxide-semiconductor devices , 1988 .

[11]  J. Maldonado,et al.  Generation and annealing of defects in silicon dioxide , 1987 .

[12]  Scofield,et al.  Evidence that similar point defects cause 1/f noise and radiation-induced-hole trapping in metal-oxide-semiconductor transistors. , 1990, Physical review letters.

[13]  K. F. Galloway,et al.  A Simple Model for Separating Interface and Oxide Charge Effects in MOS Device Characteristics , 1984, IEEE Transactions on Nuclear Science.

[14]  D. B. Brown,et al.  Defect Production in SiO2 by X-Ray and Co-60 Radiations , 1985, IEEE Transactions on Nuclear Science.

[15]  M. White,et al.  Observation of near-interface oxide traps with the charge-pumping technique , 1992, IEEE Electron Device Letters.

[16]  D. Fleetwood,et al.  Effects of oxide traps, interface traps, and ‘‘border traps’’ on metal‐oxide‐semiconductor devices , 1993 .

[17]  Daniel M. Fleetwood,et al.  Qualifying commercial ICs for space total-dose environments , 1992 .

[18]  Daniel M. Fleetwood,et al.  Thermally stimulated current measurements of SiO2 defect density and energy in irradiated metal-oxide-semiconductor capacitors , 1992 .

[19]  F. J. Grunthaner,et al.  Radiation-Induced Defects in SiO2 as Determined with XPS , 1982, IEEE Transactions on Nuclear Science.

[20]  C. L. Axness,et al.  Latent interface-trap buildup and its implications for hardness assurance (MOS transistors) , 1992 .

[21]  P. S. Winokur,et al.  Correlating the Radiation Response of MOS Capacitors and Transistors , 1984, IEEE Transactions on Nuclear Science.

[22]  Daniel M. Fleetwood,et al.  Using laboratory X-ray and cobalt-60 irradiations to predict CMOS device response in strategic and space environments , 1988 .

[23]  J. Robertson,et al.  Theory of defects in vitreous silicon dioxide , 1983 .

[24]  P. S. Winokur,et al.  Donor/acceptor nature of radiation-induced interface traps , 1988 .

[25]  Daniel M. Fleetwood,et al.  Effect of radiation-induced charge on 1/f noise in MOS devices , 1990 .

[26]  R. K. Lawrence,et al.  Post-irradiation behavior of the interface state density and the trapped positive charge , 1990 .

[27]  H. E. Boesch,et al.  Time-dependent degradation of MOSFET channel mobility following pulsed irradiation , 1989 .

[28]  D. Fleetwood,et al.  Trapped‐hole annealing and electron trapping in metal‐oxide‐semiconductor devices , 1992 .

[29]  Point defect generation during high temperature annealing of the Si‐SiO2 interface , 1993 .

[30]  H. E. Boesch,et al.  The nature of the trapped hole annealing process , 1989 .

[31]  T. R. Oldham,et al.  Spatial Dependence of Trapped Holes Determined from Tunneling Analysis and Measured Annealing , 1986, IEEE Transactions on Nuclear Science.

[32]  P. Lenahan,et al.  Spin dependent recombination: a /sup 29/Si hyperfine study of radiation-induced P/sub b/ centers at the Si/SiO/sub 2/ interface , 1990 .

[33]  James R. Schwank,et al.  Correlation of Radiation Effects in Transistors and Integrated Circuits , 1985, IEEE Transactions on Nuclear Science.

[34]  D. Fleetwood.  'Border traps' in MOS devices , 1992 .

[35]  D. Fleetwood,et al.  New insights into radiation-induced oxide-trap charge through thermally-stimulated-current measurement and analysis (MOS capacitors) , 1992 .

[36]  D. Fleetwood,et al.  Effect of bias on thermally stimulated current (TSC) in irradiated MOS devices , 1991 .

[37]  Daniel M. Fleetwood,et al.  A critical comparison of charge-pumping, dual-transistor, and midgap measurement techniques (MOS transistors) , 1993 .

[38]  Daniel M. Fleetwood,et al.  Long‐term annealing study of midgap interface‐trap charge neutrality , 1992 .

[39]  W. K. Schubert,et al.  Damage due to electron, ion, and x‐ray lithography , 1991 .

[40]  F. J. Feigl,et al.  Positive charge generation in metal‐oxide‐semiconductor capacitors , 1991 .