Index of content:
Volume 92, Issue 7, 01 October 2002
- DEVICE PHYSICS (PACS 85)
92(2002); http://dx.doi.org/10.1063/1.1502204View Description Hide Description
Boronion implantation of thermochemically polished chemical vapor deposited diamondfilms with multienergies ranging between 24 and 150 keV and a total dose of about is used to get p-type conductivity.n-type conductivity is achieved by lithiumion implantation of the diamondfilms with a single energy of 50 keV and a dose of The intrinsic areas separating the p- and n-doped regions form the active areas of the diodes into which charge carriers are simultaneously injected upon bias. Onset voltages of <10 V are due to the low concentration of nitrogen related centers in the diamondfilms. The current–voltage characteristics of the diodes manifest trap filling, Frenkel–Poole emission, thermionic emission, and space charge limited current regimes. At 300 °C, currents as high as 12 mA are measured at a forward bias of 100 V. Rectification ratios of up to about four orders of magnitude are achieved. They increase with increasing width of the i region within the measuredi region of 3–10 μm, as a result of the considerable decrease of the reverse bias current relative to the forward bias current.
Physics-based numerical modeling and characterization of 6H-silicon-carbide metal–oxide–semiconductor field-effect transistors92(2002); http://dx.doi.org/10.1063/1.1499523View Description Hide Description
A detailed analysis of silicon-carbide (SiC) metal–oxide–semiconductor field-effect-transistor (MOSFET) physics is performed. Measurements of current–voltage characteristics are taken. A device simulator is developed based on the drift–diffusion equations. The model accounts for incomplete ionization. Comprehensive mobility and interface state models are developed for SiCMOSFETs. The mobility model accounts explicitly for bulk transport, as well as for interface states, surface phonons and surface roughness. Agreement between simulated and measured terminal characteristics is obtained. The results provide values for interface state occupation as a function of energy and position along the surface. Results giving values for surface mobility as a function of position along the channel indicate that interface states have an especially strong effect on SiC operation. Our investigation indicates that substantial reduction of interface states can give rise to a fivefold increase in transconductance.
Influence of electrode configurations on the quality factor and piezoelectric coupling constant of solidly mounted bulk acoustic wave resonators92(2002); http://dx.doi.org/10.1063/1.1505977View Description Hide Description
This article presents an electrode effect on the quality factor and effective coupling coefficient empirically and theoretically. The possible quality factor detractors in film bulk acoustic wave resonator devices are the acoustic wave attenuation in the metal and piezoelectric films, the wavescattering loss due to the surface roughness, and the electrode electrical loss. Due to the small acoustic wave attenuation of the Moelectrode, the composite Mo–AlN–Mo resonator with the thick electrode provides higher Q values than the resonator with the good quality AlN film and the thin Moelectrode. In such Mo electroded resonators, the effective coupling coefficient is kept relatively high. It is found that the Q value of solidly mounted resonators (SMRs) is not determined by only the piezoelectric film quality, but by a weighted average of the electrode and piezoelectric film quality. Of Q value detractors, the scattering loss originating from surface roughness is thought to be very important factor in SMR quality value.