Measurements of Grain Boundary Trap Density and Hydrogen Diffusivity in Polycrystalline Silicon Fet's

1990 ◽  
Vol 182 ◽  
Author(s):  
Chad B. Moore ◽  
Dieter G. Ast

AbstractHydrogen diffusion in as-deposited and in oxidation-annealed polycrystalline silicon films was investigated using n-type accumulation-mode MOSFET's. The diffusion was studied by measuring the reduction in the grain boundary trap density with hydrogenation time. The number of traps in fully hydrogenated as-deposited films fell to about 45% of the initial trap state density and fell to about 20% in the oxidized-annealed films. Concurrently, the mobility increased about 95 % to 5cm2/Vs in the as-deposited films and by about 55 % to 25 cm2/Vs in the oxidized polysilicon devices. The effective preexponential diffusion coefficient and activation energy for hydrogen diffusion in the two different films were Do= 5.4×10−10 cm2/s and EA= 0.37 eV for the as-deposited polysilicon and Do=2.1×10−10 cm2/s and EA= 0.36 eV for the oxidized polysilicon.

InfoMat ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 409-423 ◽  
Author(s):  
Behzad Bahrami ◽  
Sally Mabrouk ◽  
Nirmal Adhikari ◽  
Hytham Elbohy ◽  
Ashim Gurung ◽  
...  

Author(s):  
Xin Song ◽  
Zelin Han ◽  
Bin Liu ◽  
Mu Qin ◽  
Yuancai Duo ◽  
...  

Abstract The heat affected zone (HAZ) of 2.25Cr-1Mo-0.25V welded joint is a critical part for the safety of hydrogenation reactors. Hydrogen has a significant effect on the HAZ, studying hydrogen diffusion characteristics, such as: hydrogen flux and the effective hydrogen diffusivity has a remarkable value in investigating the hydrogen-induced material degradation mechanisms. In this work, an electrochemical permeation method was applied to study the hydrogen diffusion characteristics of HAZ. Then, the metallographic microscope and a software “Image J” were used to analyze the density of grain boundaries of HAZ. The effect of the post–weld heat treatment (PWHT, i.e. annealing) on the hydrogen diffusion characteristics of HAZ was also been investigated. The results show that after PWHT, the effective hydrogen diffusivity of HAZ increases from 1.63 × 10−7cm2·s−1 to 3.68 × 10−7cm2·s−1, the hydrogen concentration decreases from 1.92 × 10−4mol·cm−3 to 1.09 × 10−4mol·cm−3, and the hydrogen trap density decreases from 3.00 × 1026m−3 to 0.76 × 1026m−3. Thus, PWHT can significantly reduce density of grain boundaries, thereby reducing the hydrogen trap density, enhancing the hydrogen diffusivity and reducing the hydrogen concentration.


1991 ◽  
Vol 30 (Part 1, No. 12B) ◽  
pp. 3715-3718 ◽  
Author(s):  
Noriji Kato ◽  
So Yamada ◽  
Yoshio Nishihara ◽  
Mario Fuse ◽  
Toshihisa Hamano

1980 ◽  
Vol 51 (3) ◽  
pp. 1576-1581 ◽  
Author(s):  
J. C. M. Hwang ◽  
P. S. Ho ◽  
J. E. Lewis ◽  
D. R. Campbell

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