Simulation of temperature cycling effects on electromigration behavior under pulsed current stress [VLSI metallization]

Gui, Xiang; Haslett, J.W.; Dew, S. K.; Brett, Michael

doi:10.1109/16.658670

Cited by 16 publications

(4 citation statements)

References 29 publications

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“…As described in our previous paper [8], the complete electrical model of the stress setup including coupling phenomenon is validated. To understand ageing impact coming from the external electromagnetic disturbance, it was important to simulate the evolution of the current induced by the coupling phenomenon at the base input of the HBT, since the phenomenon of electromigration or material movement resulting from the passage of high electrical current continues to be a major reliability concern [11]. The induced current versus time at the base of the transistor is shown in figure 1, when the probe is fed by 40 dBm at 1 GHz.…”

Section: Coupling-induced Currentmentioning

confidence: 99%

Degradation of Au–Ti contacts of SiGe HBTs during electromagnetic field stress

Alaeddine¹,

Genevois²,

Kadi³

et al. 2010

Semicond. Sci. Technol.

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This paper addresses electromagnetic field stress effects on SiGe heterojunction bipolar transistors (HBTs)' reliability issues, focusing on the relationship between the stress-induced current and device structure degradations. The origin of leakage currents and electrical parameter shifts in failed transistors has been studied by complementary failure analysis techniques. Characterization of the structure before and after ageing was performed by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). For the stressed samples, interface deformations of the titanium (Ti) thin film around all gold (Au) contacts have been clearly detected. These degradations include localized interface reaction between Au and Ti layers as well as their lateral atomic migration causing a significant reduction of Ti thickness. EDS analysis of the disordered region which is near the Si 3 N 4 interface has shown significant signals from Au. These observations could be attributed to the coupling between high current densities induced by stress and thermal effects due to local heating effects.

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Section: Coupling-induced Currentmentioning

confidence: 99%

Degradation of Au–Ti contacts of SiGe HBTs during electromagnetic field stress

Alaeddine¹,

Genevois²,

Kadi³

et al. 2010

Semicond. Sci. Technol.

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“…Therefore, this shows that the PAA film is difficult to be produced from 99% Al film at RT by the common potentiostatic method. However, the temperature fluctuation caused by Joule heating in pulse voltage conditions is different from that produced by a DC voltage [25,26]. At a low frequency of pulse voltage, thermal equilibrium is completely established in the pulse on and off periods, so the temperature difference between the pulse on and off periods is quite large [25].…”

Section: Resultsmentioning

confidence: 97%

Hybrid pulse anodization for the fabrication of porous anodic alumina films from commercial purity (99%) aluminum at room temperature

et al. 2009

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Most porous anodic alumina (PAA) or anodic aluminum oxide (AAO) films are fabricated using the potentiostatic method from high-purity (99.999%) aluminum films at a low temperature of approximately 0-10 degrees C to avoid dissolution effects at room temperature (RT). In this study, we have demonstrated the fabrication of PAA film from commercial purity (99%) aluminum at RT using a hybrid pulse technique which combines pulse reverse and pulse voltages for the two-step anodization. The reaction mechanism is investigated by the real-time monitoring of current. A possible mechanism of hybrid pulse anodization is proposed for the formation of pronounced nanoporous film at RT. The structure and morphology of the anodic films were greatly influenced by the duration of anodization and the type of voltage. The best result was obtained by first applying pulse reverse voltage and then pulse voltage. The first pulse reverse anodization step was used to form new small cells and pre-texture concave aluminum as a self-assembled mask while the second pulse anodization step was for the resulting PAA film. The diameter of the nanopores in the arrays could reach 30-60 nm.

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“…We can expect the temperature to remain nearly constant at sufficiently high frequencies, the pulse repetition time of which is much shorter than the thermal response time. 13 The decrease in temperature fluctuation can inhibit the surface damage by thermal fatigue.…”

Section: Resultsmentioning

confidence: 99%

Change of Damage Mechanism by the Frequency of Applied Pulsed DC in the Ge[sub 2]Sb[sub 2]Te[sub 5] Line

Yang

Park

You

et al. 2009

J. Electrochem. Soc.

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We investigated the damage on the Ge 2 Sb 2 Te 5 line structure by pulsed-dc stressing with various frequencies. The line immediately burnt out due to Joule heating under constant dc stress 2.5 MA/cm 2 . However, when pulsed dc 2.5 MA/cm 2 was stressed at the frequency of 5 MHz, failure due to thermal fatigue damage was observed. At higher frequency such as 10 MHz, no noticeable damage was observed, yet the compositional change in constitutive elements by electromigration was detected. The change of damage mechanism by varying of frequency is explained by the difference in thermal cycling extent in response to the pulsedcurrent operation at various frequencies, which is computed using a finite-difference method.Phase-change random access memory ͑PRAM͒ is one of the most promising candidates for the next generation of nonvolatile electrical memory due to its high scalability, high density, high endurance, fast operation speed, and low power consumption. Ge 2 Sb 2 Te 5 ͑GST͒ is most widely employed for phase-change materials in PRAM cells, and the phase of GST is reversibly switched by electrical-resistive Joule heating between amorphous with high resistivity and crystalline with low resistivity. Therefore, a high electrical current density of 10 6 -10 7 A/cm 2 is required to locally heat up GST for phase change. 1 Because of this switching mechanism, PRAM has suffered from severe thermal cycling and significant volume changes in the active region which result in large mechanical stress. This can cause interfacial delamination or compositional alteration in the device cells, which can be the origin of device failures. 2-5 Because these failures occurred in small-scale devices with complicated structure, limitations exist in identifying the physical origin of operational failures.We have studied the damage behaviors in GST line structure under repetitive pulsed-dc stressing with various frequencies. Because the line structure differs from the conventional structure of the PRAM cell, there may be a difference in damage phenomena from a real PRAM cell. However, the line structure can be used as a model system to simplify the physical origin of failures because current density and temperature profile are more uniform in this structure. The relatively wide line structure used in this study makes it easy to observe the change in microstructure and composition by the current stressing. Pulsed-dc stressing is the most appropriate testing method in investigating the reliability of PRAM which employs pulsed currents in actual operation. The frequency of an electrical pulse determines the duration time of electrical pulse and affects the extent of thermal cycling and mechanical stress. To identify the extent of thermal cycling under the testing conditions, we calculated the temperature profile of the line using the finite-difference method ͑FDM͒. 6 ExperimentalGST strip line test structures 50 m long, 2 m wide, and 300 nm thick were made using the lift-off method ͑Fig. 1a͒. The GST film was deposited at room temperature using...

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Simulation of temperature cycling effects on electromigration behavior under pulsed current stress [VLSI metallization]

Cited by 16 publications

References 29 publications

Degradation of Au–Ti contacts of SiGe HBTs during electromagnetic field stress

Degradation of Au–Ti contacts of SiGe HBTs during electromagnetic field stress

Hybrid pulse anodization for the fabrication of porous anodic alumina films from commercial purity (99%) aluminum at room temperature

Change of Damage Mechanism by the Frequency of Applied Pulsed DC in the Ge[sub 2]Sb[sub 2]Te[sub 5] Line

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