An advantage for some wide bandgap materials, that is often overlooked, is that the thermal coefficient of expansion (CTE) is better matched to the ceramics in use for packaging technology. It is ...shown that the optimal choice for uni-polar devices is clearly GaN. It is further shown that the future optimal choice for bipolar devices is C (diamond) owing to the large bandgap, high thermal conductivity, and large electron and hole mobilities. A new expression relating the critical electric field for breakdown in abrupt junctions to the material bandgap energy is derived and is further used to derive new expressions for specific on-resistance in power semiconductor devices. These new expressions are compared to the previous literature and the efficacy of specific power devices, such as heterojunction MOSFETs, using GaN are discussed.
The novel HFET design using perforated channel region under the gate reduces drain and source parasitic resistances due to the current spreading effect in the source-gate and gate-drain regions. ...Demonstrated results for AlGaN/GaN HFET show that the RONCG time constant reduces around two times using simple and robust perforated channel device processing. These results are especially important for new generations of power switching transistors.
Carrier mobility model for GaN Mnatsakanov, Tigran T; Levinshtein, Michael E; Pomortseva, Lubov I ...
Solid-state electronics,
2003, 2003-1-00, Letnik:
47, Številka:
1
Journal Article
Recenzirano
Simple analytical approximation has been obtained to describe the temperature and concentration dependencies of the low-field mobility in gallium nitride (GaN) in wide temperature (50⩽
T⩽1000 K) and ...concentration (10
14⩽
N⩽10
19 cm
−3) ranges. The dependence of the temperature
T
m at which the mobility
μ is at a maximum on the doping level is also obtained. Results obtained can be directly used for computer simulation of GaN-based devices.
A novel technique to reveal the contact and channel components of third-order nonlinearities in III-nitride heterostructure field-effect transistors (HFETs) is presented. We demonstrate close ...correspondence between the third-order intermodulation power (IM3) obtained from dc I-V's and directly from two-tone radio-frequency measurements. The transmission-line-method patterns have been used to extract separately the contact- and channel-related sources of nonlinearity. Relative contributions of mobility-field dependence and gate-bias-induced nonlinearities are compared. Contact and channel nonlinearity coefficients are found to have opposite signs, thus allowing for HFET design with contact and channel nonlinearities mutually compensating each other, which results in improved overall device linearity.
A compact analytical model of short-channel AlGaN/GaN HEMTs in the presence of a current collapse is presented. The model is based on an experimentally established trapping mechanism at the gate ...edges and relies on significant differences between the characteristic carrier capture-escape times and typical RF signal periods. For the first time, we implement the theory describing electric field distributions in the HEMT gate-to-drain spacing region, with and without trapped charge distributions. By consequently accounting for velocity saturation effects in gated and trapped regions of the device, the presented model shows good agreement with the experimental data. The model uses a minimal number of fitting parameters, most of which are physical parameters describing velocity-field dependence of the carriers.
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