Schottky characteristics of InAlAs grown by MOCVD has been evaluated. InAlAs Schottky characteristics is strongly affected by MOCVD growth temperature. The reverse current of InAlAs grown at 700°C is more than one order of magnitude larger than that for 750°C. From DLTS measurement, a large signal due to an electron trap with an activation energy of 0.45 eV has been observed in InAlAs grown at 700°C.The results of C-V , Hall and SIMS measurements suggest that the trap is acceptor-type and seems to be related not to impurities but to intrinsic defects. The mechanism of the large reverse current in InAlAs grown at 700°C is thought to be conduction through the trap. I. IntmductionInP-based InAlAdInGaAs high electron mobility transistors (HEMTs) have been developed for the optical communication systems and the wireless communication systems operating at millimeter-wave frequencies '), ' I.Although the InP-based HEMT has shown an excellent high-frequency performance of cut-off frequency over 300GHz 3)9 4), there is still a problem due to poor gate-drain breakdown voltage compared with the GaAs-based HEMT 5), @, which should be a problem from a view point of reliability. One of the reasons for its low gate-drain breakdown voltage is due to the low Schottky barrier height of InAlAs, which is a gate contact layer in InP-based HEMTs. In this paper, we describe the Schottky characteristics of InAlAs depends strongly on the growth conditions of metal organic chemical vapor deposition (MOCVD). II. ExperimentalSi-doped n-type Ino.52Alo.48As layer with the thickness of 1.4pm was grown by MOCVD on a Sdoped n-type (001) InP substrate using trimethylindium (TMI), trimethylaluminum (TMA), arsine (ASH& phosphine (PH3) and disilane (Si2H6) as source gases. The Si doping density was in the range of 4-7~10'~cm.~. The growth temperature was in the range of 680-750°C. The growth rate was 480 &min and the V/III supply ratio was 32-96.To evaluate the Schottky characteristics, AVTi Schottky and the Au-based ohmic electrodes were formed onto the InAlAs layer using EB evaporation. The area of the Schottky electrode was 0.04 mm2. The electrical properties of the grown layers were characterized using current-voltage (1-V), capacitance-voltage (C-V) and Hall measurements. Concentrations of doped Si and unintentionally doped impurities were measured by secondary ion mass spectrometry (SLMS). The deep traps formed within the grown layers were characterized using deep-level transient spectroscopy (DLTS). Figure 1 shows the Schottky characteristics for the InAlAs layers grown at 700°C and 750°C. For the growth temperature of 7OO0C, the Schottky barrier height was lower and the reverse current was more than one order of magnitude larger than that for 750°C. Figure 2 shows the temperature dependence of the Schottky barrier height and the ideality factor obtained from the thermionic emission theory. The Schottky barrier height and the ideality factor were degraded as the temperature decreased, and the temperature dependence for the InAlAs grown at 700...
It is shown that the nth-order Born approximation to the total cross section for the excitation of an atomic system by a high-energy heavy particle obtained by using the customary wave treatment is equivalent to that given by the method of impact parameters.
Schottky characteristics of InAlAs grown by metal-organic chemical vapor deposition (MOCVD) have been evaluated. InAlAs Schottky characteristics are strongly affected by MOCVD growth temperature. The reverse current of InAlAs grown at 700 • C is more than one order of magnitude larger than that at 750 • C. From deep-level transient spectroscopy (DLTS) measurements, electron traps with activation energies of 0.45, 0.33 and 0.15 eV have been observed in InAlAs grown at 700 • C.The results of C-V , Hall and secondary ion mass spectrometry (SIMS) measurements suggest that the trap is acceptor-type and seems to be related not to impurities but to intrinsic defects. The mechanism of the large reverse current in InAlAs grown at 700 • C is believed to be due to the conduction through the trap.
We have observed the degradation of pinch-off characteristics of InAlAs/InGaAs high electron mobility transistors (HEMTs) with SiN passivation film after the bias stress test, which has been resulted from an increase of leakage current on InP surface. On the other hand, the device passivated by Si02 film does not show any degradation. The stability of the isolation characteristic for InP is strongly affected by the surface passivation film formed by plasma-enhanced chemical vapor deposition (PCVD). In order to improve the device reliability, Si02 is more suitable than SiN for a stable passivation to InP surface.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.