@misc{jin_zeng_ma_barlage_2007, title={Analytical threshold voltage model with TCAD simulation verification for design and evaluation of tri-gate MOSFETs}, volume={51}, ISSN={["0038-1101"]}, DOI={10.1016/j.sse.2007.01.023}, abstractNote={Abstract The dynamics of the threshold voltage calculation is evaluated for the tri-gate architecture of device. The 3-D poisson’s equation with eight boundary conditions is solved analytically and an analytical threshold model for tri-gate Si MOSFET device is developed. TCAD simulation result of the same device structure is also presented and it agrees well with our threshold analytical model. Furthermore, this analytical threshold model is capable of doing rudimentary first order comparisons of the threshold voltage with respect to device dimensions and semiconductor material type.}, number={3}, journal={SOLID-STATE ELECTRONICS}, author={Jin, Yawei and Zeng, Chang and Ma, Lei and Barlage, Doug}, year={2007}, month={Mar}, pages={347–353} }
 @article{saripalli_pei_biggerstaff_ramachandran_duscher_johnson_zeng_dandu_jin_barlage_2007, title={Transmission electron microscopy studies of regrown GaN Ohmic contacts on patterned substrates for metal oxide semiconductor field effect transistor applications}, volume={90}, ISSN={["1077-3118"]}, DOI={10.1063/1.2741123}, abstractNote={Contact selected area regrowth of GaN was performed by metal organic chemical vapor deposition using a silicon nitride dielectric hard mask to define plasma etched recesses and to define source-drain regions. A low temperature regrowth process at 750–850°C was adopted to limit lateral overgrowth. High resolution electron microscopy images and selected area diffraction confirmed the regrowth selectivity and revealed that the low temperature regrown GaN is epitaxial and has a wurtzite crystal structure. I-V characteristics of the fabricated metal oxidesemiconductor field effect transistor show enhancement mode operation.}, number={20}, journal={APPLIED PHYSICS LETTERS}, author={Saripalli, Y. N. and Pei, L. and Biggerstaff, T. and Ramachandran, S. and Duscher, G. J. and Johnson, M. A. L. and Zeng, C. and Dandu, K. and Jin, Y. and Barlage, D. W.}, year={2007}, month={May} }
 @article{wang_park_saripalli_johnson_zeng_barlage_long_2006, title={Optical spectroscopic analysis of selected area epitaxially regrown n(+) gallium nitride}, volume={99}, ISSN={["1089-7550"]}, DOI={10.1063/1.2204755}, abstractNote={Gallium nitride (GaN) metal-insulator-semiconductor field-effect transistor with regrown by selected area metal organic vapor-phase-epitaxy n+ layer has been analyzed by micro-Raman and microphotoluminescence (micro-PL) spectroscopy. The material properties of the regrown n+ layer and the intrinsic layer in the gate region were extracted by using both spectroscopies. The free-carrier concentration of the regrown GaN layer and the intrinsic layer were determined by line shape analysis of the coupled plasmon-phonon mode to be 4.7×1017 and <3×1016cm−3, respectively. The inefficient substitutions of Ga vacancy (VGa) by Si result in relatively low carrier concentration in the regrown GaN layer. From the shift of E2(2) Raman peak and the near-band-edge (NBE) PL peak, the biaxial compressive stress in the intrinsic layer was found to be 0.4GPa. The residual stress was found to be fully relaxed in the regrown layer. The Si doping concentration in the regrown layer was determined to be 2×1019cm−3 based on the potential fluctuations introduced redshift of its NBE PL peak.}, number={12}, journal={JOURNAL OF APPLIED PHYSICS}, author={Wang, D. and Park, M. and Saripalli, Y. N. and Johnson, M. A. L. and Zeng, C. and Barlage, D. W. and Long, J. P.}, year={2006}, month={Jun} }
 @article{saripalli_zeng_long_barlage_johnson_braddock_2006, title={Properties of III-N MOS structures with low-temperature epitaxially regrown ohmic contacts}, volume={287}, ISSN={["1873-5002"]}, DOI={10.1016/j.jcrysgro.2005.10.075}, abstractNote={A significant limitation in the fabrication of III-N MOSFET relates to the formation of ohmic contacts for enhancement-mode MOSFET structures. Unlike existing III-N HFET devices, which include a high free-carrier density two-dimensional electron gas (2DEG) in the semiconductor substrate, a MOSFET in either accumulation or inversion mode require low free-carrier concentrations for the semiconductor channel to have an off-state. The applied gate bias enhances the free-carrier density in the channel, turning on the FET. Unfortunately, a low free-carrier density substrate is problematic for the formation of ohmic contacts, a problem usually dealt with in silicon MOS through self-aligned ion implantation. The high annealing temperatures associated with activating implanted dopants to substitutional sites limits the use of ion implantation for III-N MOSFET fabrication. To overcome this difficulties, selected area epitaxial re-growth of doped III-N materials was developed to form source-drain contacts on otherwise low-doped III-N epitaxial substrates, yielding the needed N+/n−/N+ or N+/p−/N+ structures. Contact re-growth was performed by MOVPE using a silicon nitride dielectric mask defining plasma-etched recesses in the source-drain region. A significant acceleration in the growth rate and surface roughening was observed following re-growth relative to a non-selective area epitaxial growth due to the reduced fill-factor, motivating a general change in MOVPE-operating conditions during re-growth. As the re-growth was intentionally designed to limit the lateral extent of the source-drain regions, the MOVPE re-growth process was performed under conditions limiting lateral overgrowth. III-N MOSFET structures with epitaxial regrown contacts are projected to provide a pathway for low threshold voltage devices suitable for amplifier or logic applications.}, number={2}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Saripalli, YN and Zeng, C and Long, JP and Barlage, DW and Johnson, MAL and Braddock, D}, year={2006}, month={Jan}, pages={562–565} }