Effects of cap layer on ohmic Ti/Al contacts to Si+ implanted GaN

Placidi, Marcel; Pérez‐Tomás, Amador; Constant, A.; Rius, Gemma; Mestres, N.; Millán, José del R.; Godignon, P.

doi:10.1016/j.apsusc.2008.12.084

Cited by 32 publications

(16 citation statements)

References 19 publications

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“…The source and drain contacts were annealed at 700°C for 90 s in Ar ambient. The contact resistance of the source and drain electrodes was determined 15 to be lower than 10 −5 ⍀ cm 2 . MOSFET characterization was performed with a set of Keithley units.…”

Section: Methodsmentioning

confidence: 99%

“…Although a protective SiO 2 cap layer has been used, a significantly pit density has been observed. 15 The rms surface roughness of the GaN surface before the gate oxide deposition, measured using an atomic force microscope, was 130 Å. AЈ is determined to be 1570 cm 4−␣3 V ␣3−1 / s K from this value. Therefore, it is clear that for our fabricated MOSFET, interface trap charge along with surface roughness plays a major role.…”

Section: ͑11͒mentioning

confidence: 96%

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GaN metal-oxide-semiconductor field-effect transistor inversion channel mobility modeling

Pérez‐Tomás

Placidi

Perpiñà

et al. 2009

Journal of Applied Physics

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Lateral n-channel enhancement-mode GaN metal-oxide-semiconductor ͑MOS͒ field-effect transistors and lateral capacitors have been fabricated on a p-type epi-GaN substrate semiconductor and electrically characterized at different temperatures. A clear positive behavior of the inversion channel mobility with temperature has been obtained. A physics-based model on the inversion charge and charge trapped in interface states characteristics has been used to investigate the temperature dependence of the inversion MOS channel mobility. The field-effect mobility increase with temperature is due to an increase in the inversion charge and a reduction in the trapped charge for a given voltage gate. Then, for larger gate bias and/or higher temperatures, surface roughness effects become relevant. The good fitting of the model with the experimental data leads us to consider that the high density of charged acceptor interface traps together with a large interface roughness modulates the channel mobility due to scattering of free carriers in the inversion layer. A closed form expression for the experimental inversion MOS channel mobility is proposed.

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Section: Methodsmentioning

confidence: 99%

Section: ͑11͒mentioning

confidence: 96%

GaN metal-oxide-semiconductor field-effect transistor inversion channel mobility modeling

Pérez‐Tomás

Placidi

Perpiñà

et al. 2009

Journal of Applied Physics

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“…GaN JBS diodes could further increase the performance of GaN-based power rectifiers in the 600 V-3.3 kV range. In this sense, we are working on the optimization of contact resistance to implanted p-type GaN [27]. We have found that protection during post-implantation annealing is very important to obtain a good uniformity on the contact properties.…”

Section: Gan Power Devicesmentioning

confidence: 99%

Wide Band Gap Semiconductor Devices for Power Electronics

2012

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It is worldwide accepted today that a real breakthrough in the Power Electronics field may mainly come from the development and use of Wide Band Gap (WBG) semiconductor devices. WBG semiconductors such as SiC, GaN, and diamond show superior material properties, which allow operation at high-switching speed, high-voltage and high-temperature. These unique performances provide a qualitative change in their application to energy processing. From energy generation (carbon, oil, gas or any renewable) to the end-user (domestic, transport, industry, etc), the electric energy undergoes a number of conversions. These conversions are currently highly inefficient to the point that it is estimated that only 20% of the whole energy involved in energy generation reaches the end-user. WGB semiconductors increase the conversion efficiency thanks to their outstanding material properties. The recent progress in the development of high-voltage WBG power semiconductor devices, especially SiC and GaN, is reviewed. The performances of various rectifiers and switches, already demonstrated are also discussed. Material and process technologies of these WBG semiconductor devices are also tackled. Future trends in device development and industrialization are also addressed. Key words: SiC, GaN, Power devices, Rectifiers, MOSFETs, HEMTsWide Band Gap poluvodički sklopivi za učinsku elektroniku. U današnje vrijeme napredak u polju učinske elektronike prvenstveno dolazi razvojem i uporabom Wide Band Gap (WGB) poluvodičkih uredaja. WBG poluvodiči kao Sic, GaN i dijamant pokazuju iznimna svojstva materijala, što omogućuje korištenje pri brzim promjenama stanja, visokim naponima i visokim temperaturama. Ova jedinstvena svojstva osiguravaju kvalitativne promjene njihovom primjenon u obradi energije. Od početnih energenata (ugljen, ulje, plin ili obnovljivi izvori) do završne faze korištenja (kućanstvo, prijevoz, industrija) električna energija prolazi kroz različite faze pretvorbe energije koje su trenutno prilično neefikasne očemu govori podatak da se samo 20% početne energije iskoristi u konačnoj fazi. WGB poluvodiči povečavaju efikasnost pretvorbe zahvaljujući izvanrednim svojstvima materijala. U radu je dan pregled nedavnog napretka u razvoju visoko-naponskih WGB poluvodiča, posebno SiC i GaN te je dan pregled svojstava predstavljenih ispravljača i sklopki. Takoder u radu su opisani materijali i tehnologija WGB poluvodičkih uredaja te je opisan budući trend u razvoju uredaja i njihovom korištenju u industriji.

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“…Moreover, it also has to be easily removed to be compatible with device processing. Many cap‐layers have been reported in the literature such as AlN, oxides and other nitrides . However, very few articles present GaN surface characterizations (AFM or SEM) after annealing and etching of the cap‐layer.…”

Section: Introductionmentioning

confidence: 99%

Impact of rapid thermal annealing on Mg-implanted GaN with a SiO_x /AlN cap-layer

Khalfaoui

Oheix

El-Zammar

et al. 2016

Phys. Status Solidi A

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Phone: þ33 2 47 42 40 00 ext: 4647, Fax: þ33 2 47 42 49 37Local p-type doping in GaN is a key issue for device development but it remains a challenge to be achieved. In this work, we studied the activation of Mg implanted in the GaN. Multi-energy implantations were performed to achieve a "box-like" profile. SIMS measurements showed unexpected deep Mg profile due to defect-assisted channeling in the GaN. In addition, a high-density defect region induced by the implantation was evidenced by TEM characterization. To protect the GaN surface prior to high temperature annealing, an AlN cap-layer was deposited by reactive sputtering followed by SiO x deposition leading to a double cap-layer. Afterwards, the capped samples were RTA-annealed at high temperatures for several minutes under nitrogen. Two types of annealing processes were applied: a monocycle and a multicycle annealing. After annealing, the double cap-layer was etched using chemical solutions. AFM characterizations, after annealing and caplayer etching, demonstrated that a GaN surface with similar roughness to as-grown samples and pit-free can be achieved after both monocycle and multicycle annealing steps. However, an AlGaN layer at the AlN/GaN interface is observed by ToF-SIMS and remained after the etching of the AlN layer. Finally, Schottky diodes were processed on the unimplanted and annealed samples, evidencing a double barrier, while P/N junction diodes are still being processed on the implanted and annealed samples.

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Effects of cap layer on ohmic Ti/Al contacts to Si+ implanted GaN

Cited by 32 publications

References 19 publications

GaN metal-oxide-semiconductor field-effect transistor inversion channel mobility modeling

GaN metal-oxide-semiconductor field-effect transistor inversion channel mobility modeling

Wide Band Gap Semiconductor Devices for Power Electronics

Impact of rapid thermal annealing on Mg-implanted GaN with a SiO_x /AlN cap-layer

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Effects of cap layer on ohmic Ti/Al contacts to Si+ implanted GaN

Cited by 32 publications

References 19 publications

GaN metal-oxide-semiconductor field-effect transistor inversion channel mobility modeling

GaN metal-oxide-semiconductor field-effect transistor inversion channel mobility modeling

Wide Band Gap Semiconductor Devices for Power Electronics

Impact of rapid thermal annealing on Mg-implanted GaN with a SiO x /AlN cap-layer

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Impact of rapid thermal annealing on Mg-implanted GaN with a SiO_x /AlN cap-layer