Results of SEE tests at NRL

SEL result

No latchups were observed in the shift register section upto 200 pJ injection, which is equivalent to LET of 600 MeV cm² mg^-1. Other sections were not tested because they are covered by a metal layer.

SEU result

Four bits in the shift register were tested their SEU-vulnerability by a 800-nm pulsed laser beam: 20th bit, 61st, 93rd, and 122nd. The entire area of each bit was scanned with defocused laser beam at first, then vulnerable spots were located by focused beam (beam diameter is approximately 1 um). SEU thershold of the spot was then sought for by changing laser intensity with the ND filter and the double-polarizer attenuator.

List of SEU-vulnerable spots in the four tested bits in the shift register

Spot ID SEU threshold Register bit the spot belongs to

Absorbed energy* (pJ) Equivalent LET (MeV cm² mg^-1) Found in SEU-resistive? Designed by SEU transition

1A
1B
1C
33.3
1.33
1.78
100.0
4.0
5.33
122nd bit Yes E. Spencer 0 to 1

2A
2B
2C
2D
> 33.3
1.78
24.4
22.2
> 100.0
5.33
73.3
66.7
93rd bit Yes E. Spencer 1 to 0

3A
155.5
466.6
61st bit Yes D. Freytag 1 to 0

4A
4B
4C
> 33.3
3.56
35.6
> 100.0
10.7
106.7
20th bit No Tanner Standard 0 to 1

*) Absorbed energy is estimated under assumption of 66 % transmission of laser beam energy through the passivation layer of the chip.

Spot ID	SEU threshold	Register bit the spot belongs to
Absorbed energy* (pJ)	Equivalent LET (MeV cm² mg^-1)	Found in	SEU-resistive?	Designed by	SEU transition
1A 1B 1C	33.3 1.33 1.78	100.0 4.0 5.33	122nd bit	Yes	E. Spencer	0 to 1
2A 2B 2C 2D	> 33.3 1.78 24.4 22.2	> 100.0 5.33 73.3 66.7	93rd bit	Yes	E. Spencer	1 to 0
3A	155.5	466.6	61st bit	Yes	D. Freytag	1 to 0
4A 4B 4C	> 33.3 3.56 35.6	> 100.0 10.7 106.7	20th bit	No	Tanner Standard	0 to 1

Last modified: Wed Jul 4 17:32:10 PDT 2001