1. Hydrogen 20071 Studying the Effect of Molecular Hydrogen on Silicon Device Radiation Response Using Gated Bipolar Transistors Jie Chen, David Wright, and Hugh Barnaby Electrical Engineering, ASU, Tempe, Az

2. Hydrogen 20072 Topics of Discussion Motivation for the study Background Initial experimental results Modeling the effect of molecular hydrogen Recent experimental results Experimental data vs. model Summary

3. Hydrogen 20073 Motivation of Study Previous experiments showed 3x increase in N it in devices in sealed packages compared to un-sealed ones. ΔNot (cm -2 )ΔNit (cm -2 ) Unsealed~1.7x10 11 ~0.8x10 11 0.00005% H 2 Sealed~1.4x10 11 ~2.5x10 11 1.3% H 2 Sealed package Unsealed package

4. Hydrogen 20074 Post-irradiation annealing in H 2 After Mrstik & Rendell, IEEE Trans. Nucl. Sci., 1991 MOSFETS exposed to 10Mrad and 1Mrad 10KeV x-rays. Post-irradiation annealing in 100%, 10%, and 1% H 2 environment. Results show increase in N it after annealing in H 2. Increase in N it

5. Hydrogen 20075 Earlier Experiments NAVSEA Crane performed HDR testing performed at NAVSEA on devices in 100% H 2 Increase in N it

6. Hydrogen 20076 Interface Trap Formation: 2 stage model Si-SiO 2 interface - + - + - + H - + fHfH t ox Ionizing radiation H xdxd H DH volume fpfp H+ - protons - Si-H (N SiH ) - dangling bond (N it ) H H+ fHfH - proton flux - hydrogen defect (D’H) H+ After Mclean TNS 1980 Rashkeev et al. TNS 2002

7. Hydrogen 20077 Model: Impact of Molecular H 2 Empty D centers H H H H H 2 molecules Molecular hydrogen reacts with empty D centers to generate more DH centers H H DH centers H H H H 2 transport into material Rad-induced holes

8. Hydrogen 20078 1D Analytical Model Note: final 1D model assumes steady state, no N it saturation or annealing Equil. H 2 - DH model Steady state hole transport (f p > 0 for all x) Proton continuity Trap continuity Final Model *

9. Hydrogen 20079 Latest Experiments GLPNP devices used are designed by NAVSEA Crane and fabricated using National’s standard linear bipolar IC process Using only devices with no- passivation (Wafer #4) for simplicity (one less parameter in modeling) 10%, 0.1%, 0.01%, 50% H2 ambient concentrations, as well as re-examination of 1% and 100% data points GLPNP with no passivation

10. Hydrogen 200710 Experimental Details 4 device samples for each H 2 concentration De-seal lids at least 3 days prior to soaking 10 -5 torr vacuum before filling of H 2 >48hrs soaking before irradiation Gamma HDR test to 30Krad at 18 rad/s Pb shield used during irradiation Devices grounded during irradiation Soaking temperature: 72 deg F Irradiation temperature: 72 deg F H 2 Chamber (Soaking & Irradiation)

11. Hydrogen 200711 Latest Experimental Results Characterization performed using Agilent 4156 SPA. Gate Sweep (GS), Subthreshold Sweep (SS), and Gummel are performed. Gate Sweep: VG = 80V to -100V, VBE = 0.5V, VC = 0V

12. Hydrogen 200712 Latest Experimental Results Subthreshold Sweep: Vg = 10V to -100V, VE = -0.1V as the drain of the pMOSFET, VC = 0V, VB = 0V.

13. Hydrogen 200713 1D model fit to data ASU results indicated monotonic increase of Nit vs ambient H 2 concentration, agrees with the predictions of the model. Saturation at high H 2 and low H 2 concentration agrees with the predictions of the model, Crane’s 100% data is different than ASU’s 100% data. The difference may be due to differences in dose, dose rate, environmental factors, etc. Re-fit of the data with the analytical model

14. Hydrogen 200714 Continuing work Post-irradiation annealing studies Effect of high pressure H 2 environment Model refinement Relate dose-rate effects to the reaction processes of hydrogen species in SiO 2 Effect of H 2 under low temperature exposure