Improved on-state performance in AlGaN-channel heterojunction field-effect transistors with a quaternary AlGaInN barrier layer and a selectively grown n++-GaN contact layer

AlN/Al0.5Ga0.5N HEMTs with heavily Si-doped degenerate GaN contacts prepared via pulsed sputtering

“…15,16) Figure 4(c) shows the R C values reported for the AlGaN HEMTs as a function of the Al composition of the AlGaN channel layer. 6,9,[16][17][18][19][20][21][22] In Fig. 4(c), conventional ohmic technologies such as regrowth contact (solid diamonds) or metal alloy contact (solid circles) show an exponential increase in the R C with Al composition.…”

“…The inset shows the TLM fitting result (e), and the contact resistance R C as a function of the Al composition in AlGaN channel layers. The solid diamonds and circles indicate the reported R C values of the regrowth contacts and metal alloy contacts, respectively 6,9,[16][17][18][19][20][21][22].…”

High drain-current-density and high breakdown-field Al0.36Ga0.64N-channel heterojunction field-effect transistors with a dual AlN/AlGaInN barrier layer

“…For the past several years, the authors have conducted intensive research on the growth of AlGaNchannel two-dimensional electron gas (2DEG) heterostructures by metalorganic chemical vapor deposition (MOCVD) and their application to HFETs. [15][16][17][18][19][20][21][22][23] Most notable topic in our past research is the proposal of strain-controlled quaternary AlGaInN barrier layers. [20][21][22][23] That is, the quaternary AlGaInN barrier layers properly designed and grown can provide smooth surface morphologies and thermal stability in addition to high 2DEG densities 20) and thereby contributed to the improvement in the device performance.…”

“…[15][16][17][18][19][20][21][22][23] Most notable topic in our past research is the proposal of strain-controlled quaternary AlGaInN barrier layers. [20][21][22][23] That is, the quaternary AlGaInN barrier layers properly designed and grown can provide smooth surface morphologies and thermal stability in addition to high 2DEG densities 20) and thereby contributed to the improvement in the device performance. 21,22) The alloy composition of the quaternary AlGaInN barriers can optimally be designed in relation to alloy compositions of the underlying AlGaN channels.…”

“…[20][21][22][23] That is, the quaternary AlGaInN barrier layers properly designed and grown can provide smooth surface morphologies and thermal stability in addition to high 2DEG densities 20) and thereby contributed to the improvement in the device performance. 21,22) The alloy composition of the quaternary AlGaInN barriers can optimally be designed in relation to alloy compositions of the underlying AlGaN channels. 20) Furthermore, most recently, we have reported that the on-state performance of AlGaInN/Al x Ga 1−x N HFETs with AlN mole fractions x of approximately 0.2 was drastically improved by adopting a regrown n ++ -GaN contact layer formed via the selective-area growth (SAG) process.…”