92 research outputs found
Thermal sensing capability and current–voltage–temperature characteristics in Pt/<i>n</i>-GaP/Al/Ti Schottky diodes
No full text We have discussed the thermal sensing capability under a constant current level and current versus voltage ( I–V) traces by measuring the temperature of high series resistance Pt/ n-GaP/Al/Ti Schottky structures in the 100−320 K range. The Rs values of 35 Ω and 4.50 × 103 kΩ for the device have been determined from I–V traces at 320 and 100 K, respectively. The thermal sensing ( V–T) curves are expected to give a straight line at each current level. However, the V–T curves have deviated upward from linearity due to the high Rs value of the device after a certain temperature. The deviation point from linearity in V–T traces shifts to higher temperatures with an increase in bias voltage and current level. Thereby, the straight-line interval portion of the V–T curve has become too small with an increase in the current value. The thermal sensing coefficient α changed from 2.49 mV/K at 10 μA to 3.21 mV/K at 0.50 nA. Therefore, it has been concluded that the Pt/ n-GaP/Al/Ti Schottky barrier (SB) is preferable for thermal sensor applications at the small current levels of 0.50, 1.0, 2.0, and 10.0 nA with high sensitivity up to a minimum temperature of 100 K. From I–V curves, [Formula: see text] and ideality factor values have ranged from 1.200 eV and 1.066 at 320 K to 0.854 eV and 1.705 at 100 K. It has been reported in the literature that the large SB height leads to a better temperature response. </jats:p
Current-voltage-measurement temperature characteristics depending on the barrier-forming contact metal thickness in Au/Cu/n-Si/Au-Sb/Ni rectifying contacts
No full textWe experimentally have introduced the current-voltage-temperature (I-V-T) characteristics of the Au/n-type Si (D1), Au/Cu/n-Si (D2), Au/Cu(4 nm)/n-Si (D3) and Au/Cu(2 nm)/n-Si (D4) Schottky-barrier diodes (SBDs) in the temperature range of 40-320 K with the step of 10 K. The copper Schottky contact (SC) dots for the D2, D3 and D4 SBDs have the thickness of 100 nm, 4 nm and 2 nm, respectively. The top Au contact has been used as a shield to prevent oxidation of the copper SC metal. The Schottky barrier height (SBH) Phi(b0) values of 0.61 eV, 0.66 eV and 0.69 eV, and the ideality factor values of 1.04, 1.04 and 1.02 for the D2, D3 and D4 SBDs have been obtained at 300 K, respectively. The SBH value has increased with decreasing Cu thin film thickness. An average series resistance R-s value of 10.6 omega has been obtained for the Au/Cu/n-Si diodes at 300 K. The obtained R-s and the ideality factor values are almost independent of the SC metal thickness. In the SBH vs temperature plots, the SBH value in the D3 and D4 diodes with 2 nm and 4 nm metal thickness almost remained unchanged from 320 K to 120 K, and in the D2 SBD from 320 K to 160 K. Therefore, it can be said from these results that the quality of the SBDs has increased with decrease in Cu Schottky film thickness
Experimental current-voltage-temperature and thermal sensitivity behaviors of an ideal Schottky barrier diode over a wide temperature range
No full textThe Pt/epitaxy n-Si/n+Si Schottky barrier diodes (SBDs) with a Schottky contact area of 9 × 10−4 cm2 were fabricated, and their experimental current-voltage (I-V) characteristics exhibited an ideal behavior in the 20-320 K range. We investigated the thermal sensitivity behavior of this SBD, which exhibits an ideal behavior. The series resistance Rs value remained approximately unchanged as 10.00 Ω at 20 K and 9.258 Ω at 320 K. A barrier height value of q Φb0= 0.807 eV at 320 K shows a slight decrease to 120 K, and the ideality factor n value shows a slight increase from 1.016 at 320 to 1.070 at 120 K. Furthermore, the sharp decrease in q Φb0 value, from 120 to 20 K, was ascribed to the barrier height inhomogeneity due to the low-barrier patches at the Pt/n-Si interface. It has been seen that the forward bias voltage-temperature (V-T) curves for the thermal sensitivity behavior have two linear regions, the low temperature region (LTR) and high temperature region (HTR), at each current level from 1.0 pA to 1.0 mA. The thermal sensitivity coefficient α from the slope of the VT curve increased with a decrease at the current level in both regions. At each current level, the V-T curves give higher α values in the HTR than those in the LTR. The α value ranged from 3.302 mV/K at 1.0 pA to 1.590 mV/K at 1.0 mA in the HTR. As a result, it was concluded that the Pt/n-Si diode can be used as a high-sensitivity thermal diode for sensor applications since its thermal sensitivity values coincide with the literature values
Numerical Analysis of Thermal Sensitivity Characteristics by Pinch-Off Model in Inhomogeneous Schottky Barrier Diodes
No full textAbstract: We have inspected the numerical simulation and the experimental voltage–temperature (V–T) traces of the Pt/epitaxy n-Si/n+Si/Au Schottky barrier diode (SBD) as a thermal sensing element, using the modified TE equation by Tung. The experimental V–T data for the thermal sensitivity have been directly measured from 10 K to 320 K with steps of 2.0 K under some forward bias current levels. It has been seen that the experimental V–T traces consist of two linear regions with different slope, which have been ascribed to the barrier inhomogeneity. A striking result of the present work is to show whether the presence of two linear regions and the non-linearity at low temperatures in the V–T curves of thermal diode may be due to barrier inhomogeneity. By accounting for the patch parameters such as the number of patches and standard deviation, σ, the fits with Tung’s model to experimental V–T curves have shown that the presence of nano-sized patches with different barrier heights in SBDs is one of the main causes of undesirable anomalies in the change of thermal sensitivity. It has been seen from fits to the experimental V–T curves that the total effective patch area and the number of patches in the high-temperature region have higher values than those in the low-temperature region. The findings strongly emphasize that the barrier inhomogeneities are the limiting factor when analyzing the thermal sensitivity of the SBDs
+Si structures as a function of Schottky contact area
No full textWe have investigated the thermal sensitivity of Pt/epitaxy n-Si/n(+)Si Schottky barrier (SB) diodes as a function of the Schottky contact (SC) area. Moreover, we have reported the current-voltage (I-V) of these SB diodes in the temperature range of 40-320 K. The V-T characteristics for the thermal sensitivity have been measured in the 20-320 K range with steps of 2 K at different current levels, which range from 10 nA to 100 mu A. The V-T curves have given two linear regions at each current level, one in the low temperature (LT) region and the other in the high temperature (HT) region. The thermal sensitivity coefficient alpha has increased with the decreasing current level for all diodes. The alpha value has increased with increasing SC area at the same current level in the LT region. The case may be attributed to the barrier inhomogeneity at low temperatures. However, in the HT region, the alpha value has decreased very slightly with increasing SC area at the same current level, which may be ascribed to the fact that the current transport occurs over a lateral homogeneous SB height at high temperatures. The SB height and ideality factor n values from the I-V-T curves have remained approximately unchanged from 170 to 320 K. Published under an exclusive license by the AVS
CURRENT–VOLTAGE CHARACTERISTICS OF THERMALLY ANNEALED Ni/n-GaAs SCHOTTKY CONTACTS
No full text The Schottky barrier type Ni/[Formula: see text]-GaAs contacts fabricated by us were thermally annealed at 600[Formula: see text]C and 700[Formula: see text]C for 1[Formula: see text]min. The apparent barrier height [Formula: see text] and ideality factor of the diodes were calculated from the forward bias current–voltage characteristic in 60–320[Formula: see text]K range. The [Formula: see text] values for the nonannealed and 600[Formula: see text]C and 700[Formula: see text]C annealed diodes were obtained as 0.80, 0.81 and 0.67[Formula: see text]eV at 300[Formula: see text]K, respectively. Thus, it has been concluded that the reduced barrier due to the thermal annealing at 700[Formula: see text]C promises some device applications. The current preferentially flows through the lowest barrier height (BH) with the temperature due to the BH inhomogeneities. Therefore, it was seen that the [Formula: see text] versus [Formula: see text] plots for the nonannealed and annealed diodes showed the linear behavior according to Gaussian distributions. </jats:p
Characteristic Diode Parameters of Thermally Annealed Ni n GaAs Schottky Contacts Over a Wide Measurement Temperature Range
No full textAn experimental study: Dependence of Schottky diode parameters on Schottky contact area size
No full textWe have investigated whether the Schottky barrier diodes (SBD) parameters such as the SB height and ideality factor (IF) change as a function of Schottky contact (SC) area, in the Pt/n-Si (D1Pt) and PtSi/n-Si (D2PtSi). The SC area ranges from 1.000x10−4 cm2 to 1.600x10−3 cm2. The results of this kind of study can help selection of SC dimensions suitable for many purposes in temperature, pressure and atmospheric gas composition sensors, and switching power, high-power, high-temperature and high-frequency devices. The IF and SB height values from the forward bias I–V curves at 296 K have ranged from 1.036 0.7716 eV for 1.00x10−4 cm2 to 1.013 and 0.7819 eV for 1.60x10−3 cm2 in the D1Pt diodes, respectively and from 1.073 and 0.8619 eV for 1.00x10−4 cm2 to 1.020 and 0.8897 eV for 1.60x10−3 cm2 in D2PtSi diodes, respectively. Thus, it has been seen that the SB height value has raised while the IF value has decreased with an increase in the SC area size. It has been concluded in literature that the increase in the SC diameter reveals decreasing periphery effect and absolute value of the built in electric field
Temperature-dependent characteristics of Tantalum and Tantalum nitride based p-Si structures
No full textWe investigated the temperature-dependent current-voltage (I-V-T) characteristics data of Ta and Ta/TaN-based p-Si Schottky barrier diodes (SBDs). The Schottky barrier heights (SBH) for Ta/p-Si and Ta/TaN1-x/p-Si SBDs were obtained as 0.574 eV and 0.717 eV at 300 K, respectively. The difference between their SBHs is 0.143 eV at 300 K. At temperatures below 240 K for the Ta/TaN1-x/p-Si, more excess current than estimated by the TE model was observed at low bias voltages in the I-V curves. The excess current increased with a decrease in temperature. The phenomenon has been ascribed to the low SBH-patches embedded at the MS interface. Moreover, the thermal sensitivity V-T data were measured from 20 K up to 320 K at 2.0 K intervals under different current levels. It has been seen that the linear portion of the V-T traces of the Ta/TaN1-x/p-Si SBDs have corresponded to a wider temperature range with more thermal sensitivity coefficient α than that of the Ta/p-Si at each current level. For example, the α values of 2.573 and 2.710 mV/K at 50 nA, and 2.070 and 2.230 mV/K at 10.0 μA have been obtained for the Ta/p-Si and Ta/TaN1-x/p-Si SBDs, respectively
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