Aging effects on bulk GaAs devices

1968 ◽  
Vol 56 (2) ◽  
pp. 236-237 ◽  
Author(s):  
M.N. Al-Moufti ◽  
S.V. Jaskolski ◽  
T.K. Ishii
Keyword(s):  
Aging Effects ◽  
Bulk Gaas ◽  
Gaas Devices

Tin-Gold Contacts for Planar Bulk GaAs Devices

1968 ◽  
Vol 24 (1) ◽  
pp. 110-114 ◽  
Author(s):  
Toshiya Hayashi ◽  
Michiyuki Uenohara ◽  
Iwao Takao
Keyword(s):  
Bulk Gaas ◽  
Gaas Devices ◽  
Gold Contacts

Prospects for GaAs-on-Si LSI Circuits

1987 ◽  
Vol 91 ◽  
Author(s):  
H. Shichijo ◽  
L.T. Tran ◽  
R.J. Matyi ◽  
J.W. Lee
Keyword(s):  
Threshold Voltage ◽  
Large Scale ◽  
Recent Progress ◽  
Ring Oscillators ◽  
Standard Process ◽  
Bulk Gaas ◽  
Gaas On Si ◽  
Recent Success ◽  
Bipolar Devices ◽  
Gaas Devices

ABSTRACTThis paper will review some of the recent progress in GaAs-on-Si devices and circuits, and discuss the issues involved in realizing large scale ICs in GaAs-on-Si wafers. With a recent success in fabricating 1 Kbit static RAMs in GaAs-on-Si wafers, it has become apparent that this material is indeed acceptable for LSI complexity circuits. GaAs MESFETs fabricated using a standard process show an excellent threshold voltage uniformity which is comparable to that for bulk GaAs devices. GaAs bipolar devices on GaAs-on-Si have realized a gain of 25 which is the highest reported for bipolar devices in GaAs-on-Si material. Bipolar ring oscillators and 256-bit ROMs consisting of more than 100 gates have also been realized. In spite of these successes, however, there are numerous issues that need to be solved before this material becomes practical.

High power RF generation with optically activated bulk GaAs devices

2003 ◽  
Author(s):  
A. Kim ◽  
M. Weiner ◽  
R. Youmans ◽  
P. Herczfeld ◽  
A. Rosen
Keyword(s):  
High Power ◽  
Bulk Gaas ◽  
Gaas Devices

Subnanosecond risetime high power pulse generation using photoconductive bulk GaAs devices

1990 ◽  
Author(s):  
A. H. Kim ◽  
Maurice Weiner ◽  
Robert J. Youmans ◽  
Robert J. Zeto
Keyword(s):  
High Power ◽  
Pulse Generation ◽  
Bulk Gaas ◽  
Power Pulse ◽  
Gaas Devices ◽  
High Power Pulse

Using the secondary electrons (SE) of SEM with NIST‘s MONSEL-II program to obtain improved linewidth measurements and slope angles of line edges on a MMIC GaAs device

1996 ◽  
Vol 54 ◽  
pp. 944-945
Author(s):  
Richard G. Sartore
Keyword(s):  
Integrated Circuits ◽  
Plasma Etching ◽  
Microwave Integrated Circuits ◽  
Monolithic Microwave Integrated Circuits ◽  
Thick Gold ◽  
Gaas Devices ◽  
Source Distance ◽  
Margin Of Error ◽  
Dimensional Measurements ◽  
Barrier Metal

In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10 % to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The final measurements were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1.

Effects of Aging on the Subcortical Encoding of Stop Consonants

2020 ◽  
Vol 29 (3) ◽  
pp. 391-403
Author(s):  
Dania Rishiq ◽  
Ashley Harkrider ◽  
Cary Springer ◽  
Mark Hedrick
Keyword(s):  
Older Adults ◽  
Repeated Measures ◽  
Mixed Model ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Aging Effects ◽  
Formant Frequency ◽  
Place Of Articulation ◽  
Second Formant ◽  
Effects Of Aging

Purpose The main purpose of this study was to evaluate aging effects on the predominantly subcortical (brainstem) encoding of the second-formant frequency transition, an essential acoustic cue for perceiving place of articulation. Method Synthetic consonant–vowel syllables varying in second-formant onset frequency (i.e., /ba/, /da/, and /ga/ stimuli) were used to elicit speech-evoked auditory brainstem responses (speech-ABRs) in 16 young adults ( M age = 21 years) and 11 older adults ( M age = 59 years). Repeated-measures mixed-model analyses of variance were performed on the latencies and amplitudes of the speech-ABR peaks. Fixed factors were phoneme (repeated measures on three levels: /b/ vs. /d/ vs. /g/) and age (two levels: young vs. older). Results Speech-ABR differences were observed between the two groups (young vs. older adults). Specifically, older listeners showed generalized amplitude reductions for onset and major peaks. Significant Phoneme × Group interactions were not observed. Conclusions Results showed aging effects in speech-ABR amplitudes that may reflect diminished subcortical encoding of consonants in older listeners. These aging effects were not phoneme dependent as observed using the statistical methods of this study.

Age Differences in Eye Movements During Reading: Degenerative Problems or Compensatory Strategy?

2019 ◽  
Vol 24 (4) ◽  
pp. 297-311
Author(s):  
José David Moreno ◽  
José A. León ◽  
Lorena A. M. Arnal ◽  
Juan Botella
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Meta Analysis ◽  
Age Groups ◽  
Behavioral Changes ◽  
Aging Effects ◽  
Movement Data ◽  
Sentence Reading ◽  
The Difference ◽  
Eye Movements During Reading

Abstract. We report the results of a meta-analysis of 22 experiments comparing the eye movement data obtained from young ( Mage = 21 years) and old ( Mage = 73 years) readers. The data included six eye movement measures (mean gaze duration, mean fixation duration, total sentence reading time, mean number of fixations, mean number of regressions, and mean length of progressive saccade eye movements). Estimates were obtained of the typified mean difference, d, between the age groups in all six measures. The results showed positive combined effect size estimates in favor of the young adult group (between 0.54 and 3.66 in all measures), although the difference for the mean number of fixations was not significant. Young adults make in a systematic way, shorter gazes, fewer regressions, and shorter saccadic movements during reading than older adults, and they also read faster. The meta-analysis results confirm statistically the most common patterns observed in previous research; therefore, eye movements seem to be a useful tool to measure behavioral changes due to the aging process. Moreover, these results do not allow us to discard either of the two main hypotheses assessed for explaining the observed aging effects, namely neural degenerative problems and the adoption of compensatory strategies.

Sign in / Sign up

Export Citation Format

Share Document