Impact ionization and quantum confinement effects on the microwave performance of narrow bandgap channel millimeter-wave HFETs
Bibliographic record
Abstract
Millimeter-wave heterostructure field-effect transistors (HFETs) incorporate (Ga,In)As channels with increasingly high indium mole fractions to maximize operating frequencies and minimize noise figures. The ever shrinking channel energy gaps render the devices more susceptible to impact ionization effects. Until recently, the effects of impact ionization on the microwave performance of narrow bandgap channel HFETs have largely been ignored. In the present work, we studied the effects of impact ionization and quantum confinement on the microwave characteristics of narrow bandgap InAs-AlSb millimeter-wave HFETs. In the course of this study, we systematically varied the level of impact ionization in HFETs through the use of quantum confinement and bias conditions, and compared the microwave behavior of InAs-AlSb HFETs (with different quantum well widths) to that of conventional GaAs MESFETs also fabricated in our laboratory. The observed trends in the S-parameter data have enabled us to identify the physical effects of impact ionization on the microwave behavior of narrow-gap channel HFETs. We found that the conventional FET equivalent circuit model is inadequate when devices operate under high impact.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".