Low-offset NpN InP-GaAsSb-InP double heterojunction bipolar transistors with abrupt interfaces and ballistically launched collector electrons
Bibliographic record
Abstract
We have developed MOCVD-grown, C-doped, abrupt heterojunction InP-GaAsSb-InP DHBTs which feature a very small V/sub CE/ offset voltage <0.1 V and a low turn-on voltage (J/sub c/=1 A/cm/sup 2/) at V/sub BE/=0.3 V, by taking advantage of the staggered band line-up at InP-GaAsSb interfaces: the GaAsSb conduction band sits above the InP conduction band, eliminating any possibility of current blocking at the B-C junction; instead, the GaAsSb base injects electrons ballistically (with ΔE/sub C/=0.1-0.3 eV) into the widegap InP collector when they travel with a high saturated drift velocity and low rates of impact ionization. One of the fundamental advantages of InP-GaAsSb-InP DHBTs is that they can be implemented without compositional grading and with nominally abrupt interfaces: the turn-on and offset voltages are therefore determined by the band line-ups, doping, and junction areas. They are not altered by the effectiveness of compositional grading or pulse doping schemes that are intended to eliminate conduction-band spikes and barriers. Other important advantages of MOCVD-grown GaAsSb bases are that they can be C-doped to 10/sup 20/ cm/sup -3/ without H-passivation effects, and that the low p-type Schottky barrier heights on antimonide compounds lead to low resistance base ohmic contacts, with measured base contact resistances lower than 10/sup -7/ Ωcm/sup -2/. Our DHBT prototypes display a base current ideality factor of n/sub B/=1.1 and a current gain of 15. The fabrication of InP-GaAsSb-InP DHBTs is presented, with particular attention to the growth details and their impact on device performance.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.004 | 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 teacher head, 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".