Temperature dependence of 1/f noise in Ni/n-GaN Schottky barrier diode

Abstract

1/f noise measurements were performed on Ni/n-GaN Schottky barrier diode under forward bias over a wide temperature range from 80 to 300 K. The noise spectra exhibited frequency dependence proportional to 1/f 0 with c varying between 0.8 and 1.1 down to 1 Hz. The spectral power density of current fluctuations, S I , was found to decrease with increase in temperature. Current-voltage (I-V) characteristics of the diodes have been measured, and metal-semiconductor interface was found to be spatially inhomogeneous in the temperature range 80-300 K. The decrease in 1/f noise with increase in temperature is explained within the framework of spatial inhomogeneities model. V C 2012 American Institute of Physics. [http://dx.

Effect of rapid thermal annealing on barrier height and 1/f noise of Ni/GaN Schottky barrier diodes

“…18 GaN based SBDs with barrier heights around 1.0 eV using different metals, like Pt, Pd, Ni, etc., have been already demonstrated. [23][24][25][26][27] As thermal stability of metal contacts is important for device operations at high temperatures and in harsh environments, several authors studied the effect of high temperature furnace annealing on Schottky barrier parameters in GaN based devices. [28][29][30][31] In most of these reports, furnace annealing is done for a relatively longer period (5-60 min) where Schottky barriers are found to degrade with increase in annealing temperature.…”

“…Prior to Ohmic metallization, samples are ultrasonically cleaned using standard procedure. 25 metal mask. RTA of the Ohmic contacts is performed in N 2 ambient at 750 C for 30 s to improve the Ohmic contact quality.…”

“…Temperature dependent I-V characteristics from 80 to 320 K are performed by loading devices in a liquid He cryostat where temperature is stabilized within 0.1 K using a Lakeshore temperature controller (model 332). For 1/f noise measurements, 25 a battery generated current of 1 lA is applied across the diodes stabilized at 300 K. The voltage developed across the diode is ac coupled with the pre-amplifier (Stanford Research Systems, model 560), which blocks the non-fluctuating signal and allows only fluctuating signal to pass through it. The fluctuating signal is fed to a fast Fourier transform dynamic signal analyser (Stanford Research Systems, model 785) that displayed the spectral power density of voltage fluctuations ðS V Þ as a function of frequency in real time.…”

“…It is well known that barrier inhomogeneities at MS interface in SBDs fabricated on GaN directly affect the device characteristics. 25,27,35,36 Higher level of barrier inhomogeneities results in increase in g and decrease in / b0 : Therefore, improved g and / b0 after RTA treatment may be due to reduced level of barrier inhomogeneities. As diodes treated at 450 C for 60 s showed the best barrier characteristics, so we focussed our study on as-deposited and RTA treated (450 C/60s) diodes, which are named as D0 and D450/60 s, respectively, henceforth.…”

Investigation of significantly high barrier height in Cu/GaN Schottky diode

“…19 In addition to this, IF of 1.04 and higher SBH of 1.15 eV were calculated from I-V measurements for Cu/n-GaN, as compared to the values for Ni/n-GaN where IF and SBH were found to be 1.05 and 0.97 eV, respectively. From the previous reports on Ni/n-GaN Schottky barrier diodes, [13][14][15][16] it has been observed that in this metal/semiconductor diode, the SBH lied in between the values predicted by the Schottky-Mott model 20,21 (φ B = φ m − χ) and the Bardeen model 22 (φ B = (E g /q) − φ o ). Here, φ B is the SBH, φ m is the metal work function, χ is the electron affinity of the semiconductor, E g is the bandgap of the semiconductor, q is the electronic charge and φ o is the energy location of the charge neutrality level.…”