Fabrication of high performance GaN modulation doped field effect transistors
Bibliographic record
Abstract
Fabrication of GaN devices presents a number of processing issues. Since the AlGaN/GaN material and sapphire substrates are transparent in the ultraviolet, light scattering can degrade the quality of the lithography. GaN and AlGaN are chemically inert materials, highly resistant to wet etching. Schottky contacts are fabricated with noble metals (Pt, Au) which present adhesion problems. The approaches to solving these difficulties and the routes to fabrication of high performance GaN-based modulation doped field effect transistors are presented. The light scattering has been addressed by the deposition of amorphous Si on the backside of the wafers. Mesa etching for device isolation has been performed with both chemically assisted ion beam etching and a newly developed wet etching technique. Finally, metal adhesion has been greatly improved by the initial deposition of a thin sputtered Pt layer, followed by a thick layer of Pt/Au by e-beam evaporation. A 100 μm wide device showed a maximum dc current density of 946 mA/mm, a peak transconductance of 160 mS/mm, a short circuit current gain cutoff frequency of 15.6 GHz, and a maximum oscillation frequency of 49.4 GHz.
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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 | 0.000 |
| 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) | 0.002 | 0.001 |
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".