RF Performance of Ultra-wide Band Gap HEMTs
51
Fig. 1 a On-resistance versus breakdown voltage, b R on × Q g versus breakdown voltage
not only reduce the on-resistance but the input capacitance as well and particularly
a low gate charge (Q g ). And another important FOM, the product term Q g × R on
[5], for switching efficiency for different device families are shown in Fig. 1b. The
UWBG HEMTs have the key features: large carrier concentration, quantum well
confinement due to large conduction band offset at the heterojunction led very-high
electron mobility, results in higher current density with low R ON , make them highly
suitable for switching and RF applications [6].
Lower switching losses of UWBG HEMTs facilitates higher switching frequencies which further allows reduced size of passive components: inductors and capacitors and finally guarantees significant reduction in volume and weight of these systems; new possibilities can be explored for system applications [7, 8]. It is established
that an ideal power switching device should have small R ON and high V Br ; High
breakdown devices should have sufficiently large drift regions; but R ON increases
due to more and more resistive elements are added to the device, so device technologies showing high V Br with comparably small drift regions would find an optimum
solution [7].
THz frequency region is still less explored, and nowadays in strong demand in
variety of applications: basic science—biochemical spectroscopy, astronomy, and
materials science to practical science—environmental science, medicine, agriculture,
and security [7]. Due to low photon energy (1–100 meV) in THz regime, it can be
transmitted through non-metallic materials; though x-ray photons can also traverse
through objects opaque to visible lights, their high energy ionizes the molecules of the
objects which results in cancer for live tissues [7, 9], degradation of semiconductor
devices [10]. Although adverse effects of intense THz radiation on DNA is reported,
THz wave considered more safe than x-ray in many areas: security, detection of
drugs trafficking and hazardous materials, agriculture, water-content monitoring,
and medicine, imaging of cancer cells [7]. In spite of the emerging THz applications,
THz systems are affected by two major problems: photon energy of the THz wave is
much lower than band gap energy of semiconductors and low spatial resolution due
to much longer wavelengths of the THz waves compared to those of visible light [7].
51
Fig. 1 a On-resistance versus breakdown voltage, b R on × Q g versus breakdown voltage
not only reduce the on-resistance but the input capacitance as well and particularly
a low gate charge (Q g ). And another important FOM, the product term Q g × R on
[5], for switching efficiency for different device families are shown in Fig. 1b. The
UWBG HEMTs have the key features: large carrier concentration, quantum well
confinement due to large conduction band offset at the heterojunction led very-high
electron mobility, results in higher current density with low R ON , make them highly
suitable for switching and RF applications [6].
Lower switching losses of UWBG HEMTs facilitates higher switching frequencies which further allows reduced size of passive components: inductors and capacitors and finally guarantees significant reduction in volume and weight of these systems; new possibilities can be explored for system applications [7, 8]. It is established
that an ideal power switching device should have small R ON and high V Br ; High
breakdown devices should have sufficiently large drift regions; but R ON increases
due to more and more resistive elements are added to the device, so device technologies showing high V Br with comparably small drift regions would find an optimum
solution [7].
THz frequency region is still less explored, and nowadays in strong demand in
variety of applications: basic science—biochemical spectroscopy, astronomy, and
materials science to practical science—environmental science, medicine, agriculture,
and security [7]. Due to low photon energy (1–100 meV) in THz regime, it can be
transmitted through non-metallic materials; though x-ray photons can also traverse
through objects opaque to visible lights, their high energy ionizes the molecules of the
objects which results in cancer for live tissues [7, 9], degradation of semiconductor
devices [10]. Although adverse effects of intense THz radiation on DNA is reported,
THz wave considered more safe than x-ray in many areas: security, detection of
drugs trafficking and hazardous materials, agriculture, water-content monitoring,
and medicine, imaging of cancer cells [7]. In spite of the emerging THz applications,
THz systems are affected by two major problems: photon energy of the THz wave is
much lower than band gap energy of semiconductors and low spatial resolution due
to much longer wavelengths of the THz waves compared to those of visible light [7].