Analysis of electrical and optical properties of insulating film–GaAs interfaces using MESFET-type structures

Applied Physics Letters

1999

Section: Department Of Materials Science and Engineering Pohang Univmentioning

confidence: 99%

Determination of energy levels of surface states in GaAs metal–semiconductor field-effect transistor using deep-level transient spectroscopy

Applied Physics Letters

1999

“…4,5 The negative transconductance dispersion, commonly observed in GaAs metalsemiconductor field-effect transistors, was believed to be due to the surface states existing on the ungated regions between gate and source/drain electrodes. 1,6,7 The magnitude of the negative transconductance dispersion was dependent on the surface leakage current from the gate 1 and could be reduced after the surface passivation with Si 3 N 4 . 6 On the other hand, the positive transconductance dispersion was observed in HEMT with the source layer of Si-doped AlGaAs, which was thought to be due to bulk traps, such as DX center and point defects produced by the neutron irradiation.…”

Section: Hyung Mo Yoomentioning

confidence: 99%

“…2, observed at the negative gate bias of Ϫ0.2 V, is interpreted to be related to the surface states at the ungated region between gate and source/drain electrodes. 1,6,7 At frequencies lower than the characteristic frequency of electrons in surface states, electrons occupied in the surface states are able to follow the applied sinusoidal signal. Thus, depletion layers under the ungated and gated regions are simultaneously modulated.…”

Section: Hyung Mo Yoomentioning

confidence: 99%

Effects of deep levels on transconductance dispersion in AlGaAs/InGaAs pseudomorphic high electron mobility transistor

Applied Physics Letters

Yoo

1999

“…Oxygen atoms chemisorbed at the clean surface of GaAs can induce point defects through the dissipation of the heat of condensation, resulting in the formation of point defects below the surface, such as vacancies and antisites. 1 Surface states act as recombination centers for free carriers, leading to undesirable electrical properties, such as transconductance dispersion, 2,3 hysteresis in current-voltage (I -V) characteristics, 4 reduction of free carriers in the channel, 5 and low breakdown voltage behavior 6 in fieldeffect transistors ͑FETs͒. The magnitude of transconductance dispersion depending on surface leakage current from the gate 4 could be reduced after surface passivation with Si 3 N 4 .…”

Section: Introductionmentioning

confidence: 99%

Surface states on n-type Al0.24Ga0.76As characterized by deep-level transient spectroscopy

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

2001

Articles you may be interested inSurface states on n-type Al 0.24 Ga 0.76 As were studied using capacitance deep-level transient spectroscopy ͑DLTS͒. Two types of hole-like traps ͑labeled as H1 and H2 in this work͒ were observed in a Al 0.24 Ga 0.76 As/In 0.22 Ga 0.78 As pseudomorphic high-electron-mobility transistor with a multifinger gate. But, no hole-like traps were observed in the fat field-effect transistor ͑FATFET͒ having a negligible ratio of the ungated surface to the total area between the source and the drain. This provides evidence that the hole-like trap peaks in the DLTS spectra originated from surface states at the ungated Al 0.24 Ga 0.76 As regions exposed between gate and source/drain electrodes. The activation energies for both surface states were determined to be 0.50Ϯ0.03 and 0.81Ϯ0.01 eV. The comparison of activation energies of the two surface states with the Schottky barrier height 0.66Ϯ0.01 eV suggests that H1 and H2 are deeply related to the Fermi energy pinning levels at the Al 0.24 Ga 0.76 As surface.