Diamond delta doped structures exhibiting ultra-sharp interfaces
Résumé
Boron delta-doping of diamond has appeared as a promising viable approach for the fabrication of high performance RF power transistors taking advantage of diamond properties. Here structures based on p-/p+/p- multilayers were synthesised on (100) HPHT Ib substrates using MPCVD. An original gas injector system was developed enabling to significantly improve the sharpness of both interfaces between p+ and p- layers with a good reproducibility. SIMS profiles recorded on the doping transients still demonstrate an asymmetry of the interface sharpness from 7nm/decade to 2nm/dec on the p-/p+ and the p+/p- interfaces, respectively. The observed differences are here explained and confirmed experimentally, and result from the combination of ion mixing with the effect of the surface roughness, thus limiting the SIMS resolution in depth. The MRI (Mixing Roughness Information) model then allows to evaluate the real value of the delta thickness achievable using this technique to 7 nm and the negative and positive gradients to identical values, namely of 1.4 nm/dec.
Mots clés
- microwave-plasma-enhanced chemical vapor deposition
- HPHT substrates
- MPCVD
- gas injector system
- secondary ion mass spectrometry
- SIMS profiles
- ion mixing combination
- MRI model
- mixing roughness information
- surface roughness
- semiconductor doping
- Diamond Delta Structures
- diamond delta doped structures
- Boron
- high pressure high temperature substrates
- RF power transistors
- boron delta-doping
- ultrasharp interfaces
- secondary ion mass spectroscopy
- size 7 nm
- radiofrequency integrated circuits
- plasma CVD
- microwave power transistors
- Doping
- Nonhomogeneous media
- Radio frequency
- Microwave theory and techniques
- Substrates
- Diamond
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