Assessment of the Analytical Capabilities of Scanning Capacitance and Scanning Spreading Resistance Microscopy Applied to Semiconductor Devices

Stangoni, Maria; Ciappa, Mauro; Fichtner, W.

doi:10.1016/j.microrel.2005.07.058

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…The cross sections were prepared by manual cleaving, and the SSRM resistance was extracted from the measured current by applying a dc bias between a Ti-Pt covered silicon tip and the sample mounted to the sample holder using conductive silver paste. Only a qualitative interpretation of the SSRM signal variations in terms of carrier concentration change is typically possible because of nonlinearity originating from ͑i͒ SSRM signal to resistivity conversion 30 and ͑ii͒ that resistivity itself is a product of carrier concentration and mobility. In addition, the SSRM signal depends on the contact resistance in the tip-sample circuit and is not identical in different ͑even sequential͒ measurements because of, e.g., tip degradation.…”

Section: Methodsmentioning

confidence: 99%

Vacancy clustering and acceptor activation in nitrogen-implanted ZnO

et al. 2008

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The role of vacancy clustering and acceptor activation on resistivity evolution in N ion-implanted n-type hydrothermally grown bulk ZnO has been investigated by positron annihilation spectroscopy, resistivity measurements, and chemical profiling. Room temperature 220 keV N implantation using doses in the low 10 15 cm −2 range induces small and big vacancy clusters containing at least 2 and 3-4 Zn vacancies, respectively. The small clusters are present already in as-implanted samples and remain stable up to 1000°C with no significant effect on the resistivity evolution. In contrast, formation of the big clusters at 600°C is associated with a significant increase in the free electron concentration attributed to gettering of amphoteric Li impurities by these clusters. Further annealing at 800°C results in a dramatic decrease in the free electron concentration correlated with activation of 10 16 -10 17 cm −3 acceptors likely to be N and/or Li related. The samples remain n type, however, and further annealing at 1000°C results in passivation of the acceptor states while the big clusters dissociate.

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Section: Methodsmentioning

confidence: 99%

Vacancy clustering and acceptor activation in nitrogen-implanted ZnO

et al. 2008

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“…The SSRM resistance is extracted from the measured current by applying a dc bias between a Ti-Pt-covered silicon tip and the sample so that the signal is proportional to the sample resistivity. 13 SCM was carried out using a similar circuit in dC / dV mode. 13 Positron annihilation spectroscopy ͑PAS͒ was used to monitor open volume defects in the samples, specifically the behavior of zinc vacancies ͑V Zn ͒, the dominant irradiationinduced defect detected by PAS in ZnO at room temperature.…”

mentioning

confidence: 99%

“…13 SCM was carried out using a similar circuit in dC / dV mode. 13 Positron annihilation spectroscopy ͑PAS͒ was used to monitor open volume defects in the samples, specifically the behavior of zinc vacancies ͑V Zn ͒, the dominant irradiationinduced defect detected by PAS in ZnO at room temperature. 14 PAS is based on positron trapping at neutral and negative vacancy defects, which modifies the annihilation characteristics including the Doppler broadening of the 511 keV annihilation line.…”

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confidence: 99%

Deactivation of Li by vacancy clusters in ion-implanted and flash-annealed ZnO

et al. 2006

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Li is present in hydrothermally grown ZnO at high concentrations and is known to compensate both n-and p-type doping due to its amphoteric nature. However, Li can be manipulated by annealing and ion implantation in ZnO. Fast, 20 ms flash anneals in the 900-1400°C range result in vacancy cluster formation and, simultaneously, a low-resistive layer in the implanted part of the He-and Li-implanted ZnO. The vacancy clusters, involving 3-4 Zn vacancies, trap and deactivate Li, leaving other in-grown donors to determine the electrical properties. Such clusters are not present in sufficient concentrations after longer ͑1 h͒ anneals because of a relatively low dissociation barrier ϳ2.6± 0.3 eV, so ZnO remains compensated until Li diffuses out after 1250°C anneals.ZnO has great potential as a material for optoelectronic applications. 1,2 Hydrothermally ͑HT͒ grown ZnO material is of particular interest, as this growth method is scalable. 3 However, electronic doping issues in ZnO in general, and in HT ZnO in particular, are not fully controlled or understood. For example, the role of lithium needs to be addressed. HT ZnO is synthesized in a solution containing LiOH and is therefore abundant with Li. Lithium's lattice position decides whether it exhibits donor-or acceptorlike character in ZnO; occupying zinc sites ͑Li Zn ͒ it is an acceptor, occupying interstitial sites ͑Li i ͒ it is a donor. 4-6 This amphoteric behavior 7 explains why Li doping produces highly resistive or even semi-insulating 8 material. Interestingly, it has recently been reported that in sputtered thin ZnO films Li may act as a dominating p-type dopant. 9 However, the atomistic doping mechanism is not well understood, and the doping efficiency depends strongly on the sputtering and annealing conditions. 9 It is thus important to investigate if and how Li can be ͑i͒ stabilized as Li Zn or Li i , ͑ii͒ deactivated or gettered, or ͑iii͒ removed from the HT ZnO material. Either scenario would facilitate electronic doping, minimizing compensation by amphoteric Li.Ion implantation introduces intrinsic defects, and in some cases electronic states associated with the implanted impurity. However, activation of the implanted impurities by annealing results in limited modifications in the conductivity of the highly resistive HT ZnO, 10 presumably because of the amphoteric role of Li. The measurements in Ref. 10 were performed on highly Li-contaminated samples employing conventional anneals at temperatures Շ1000°C; these conditions were probably insufficient to remove Li from the samples, but sufficient to promote Li amphoteric behavior. In this work we report on how an extremely fast heat treatment ͑ϳ20 ms͒, so called flash annealing, influences the interaction between Li and the implantation-induced defects and how it affects the electrical properties of the ion-implanted ZnO. We have used two types of ions, He + and Li + . The former generates intrinsic defects only, whereas the latter, in addition, alters the Li concentration in the sample. Thus, we are able to ...

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“…The samples were also characterized using a Digital Instruments Nanoscope IIIa Multimode Atomic Force Microscope (AFM) using a C-AFM electrical extension named "Resiscope", which allows one to get an electrical map in parallel to the topography when measuring the current flowing through the tip [42,43]. For these measurements a bias voltage is applied between the tip and the back side of the sample.…”

Section: Nanoscale Characterizationmentioning

confidence: 99%

Observation of photovoltaic effect within locally doped silicon nanojunctions using conductive probe AFM

et al. 2020

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Localized p-doped nanojunctions (200-300 nm in diameter) were formed in n-type crystalline silicon substrates and were characterized using scanning electron microscopy (SEM) and conductive-probe atomic force microscopy (C-AFM). Localized doping was performed by diffusion through sub-micron sized holes in a silicon-oxide mask defined using self-organized polystyrene nanoparticles. After oxide removal, a significant brightness contrast in the SEM top and side view images strongly suggested the successful local doping of these areas. Furthermore, local current-voltage measurements performed by C-AFM revealed an open circuit voltage and a short-circuit current only in the areas defined as nanojunctions. This photovoltaic effect is driven by the laser used to control cantilever deflection in the AFM.

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Assessment of the Analytical Capabilities of Scanning Capacitance and Scanning Spreading Resistance Microscopy Applied to Semiconductor Devices

Cited by 6 publications

References 7 publications

Vacancy clustering and acceptor activation in nitrogen-implanted ZnO

Vacancy clustering and acceptor activation in nitrogen-implanted ZnO

Deactivation of Li by vacancy clusters in ion-implanted and flash-annealed ZnO

Observation of photovoltaic effect within locally doped silicon nanojunctions using conductive probe AFM

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