Improvement of p-Type AlGaN Conductivity with an Alternating Mg-Doped/Un-Doped AlGaN Layer Structure

Using molecular beam epitaxy, we prepared seven p-type AlGaN samples of ~25% in Al content, including six samples with Mg-doped/un-doped AlGaN alternating-layer structures of different layer-thickness combinations, for comparing their p-type performances. Lower sheet resistance and higher effective hole mobility are obtained in a layer-structured sample, when compared with the reference sample of uniform Mg doping. The improved p-type performance in a layer-structured sample is attributed to the diffusion of holes generated in an Mg-doped layer into the neighboring un-doped layers, in which hole mobility is significantly higher because of weak ionized impurity scattering. Among the layer-structured samples, that of 6/4 nm in Mg-doped/un-doped thickness results in the lowest sheet resistance (the highest effective hole mobility), which is 4.83 times lower (4.57 times higher) when compared with the sample of uniform doping. The effects of the Mg-doped/un-doped layer structure on p-type performance in AlGaN and GaN are compared.

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Improved Mobilities and Resistivities in Modulation-Doped P-type AlGaN / GaN Superlattices

MRS Proceedings ◽

10.1557/proc-693-i12.11.1 ◽

2001 ◽

Vol 693 ◽

Author(s):

Erik L. Waldron ◽

John W. Graff ◽

E. Fred Schubert ◽

Amir M. Dabiran

Keyword(s):

Standard Sample ◽

Variable Temperature ◽

Impurity Scattering ◽

Two Dimensional ◽

Polarization Effects ◽

Ionized Impurity Scattering ◽

Capacitance Voltage ◽

Superlattice Structures ◽

P Type ◽

Mg Doped

AbstractP-type AlGaN / GaN superlattice structures have demonstrated higher acceptor activation due to a modulated valence band resulting from the superlattice as well as spontaneous and piezoelectric polarization fields. The polarization effects are due to the wurtzite structure of AlGaN and the strain present in AlxGa1-xN / GaN heterostructures. Variable temperature Hall effect studies of Mg doped Al0.20Ga0.80N / GaN superlattices reveal an improvement in resistivity and mobility for modulation-doped structures versus uniformly doped structures. Very low resistivities less than 0.1 & cm and hole mobilities ~ 36 cm2/V s are demonstrated. This improvement is attributed to a reduction of neutral and ionized impurity scattering for the two-dimensional hole gas present in the GaN layers of the modulation-doped superlattice. The improvement is greatest at temperatures below ~ 150 K. The doped regions of the superlattices have Mg concentrations of ~1019 cm-3. Two modulation-doped samples were grown by MBE: a standard scheme with dopants only in the AlGaN barriers, and a shifted scheme with dopants concentrated near the AlGaN / GaN interfaces. The standard sample has mobilities of 8.9 and 36 cm2/V s at 300 and 90 K, respectively. Resistivities of the standard sample are 0.21 and 0.068 Ω cm at 300 and 90 K, respectively. Carrier concentrations for this sample are 3.4 and 2.5 x 1018 cm-3 at 300 and 90 K, respectively. Capacitance-voltage profiling on the samples shows a clear indication of a two-dimensional hole gas as well as the periodicity of the superlattice.

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Photoluminescence Characterization of p-type GaN:Mg

MRS Proceedings ◽

10.1557/proc-482-673 ◽

1997 ◽

Vol 482 ◽

Author(s):

Dorina Corlatan ◽

Joachim Krüger ◽

Christian Kisielowski ◽

Ralf Klockenbrink ◽

Yihwan Kim ◽

...

Keyword(s):

Layer Structure ◽

Growth Conditions ◽

Buffer Layers ◽

Near Band Edge ◽

Acceptor Pair ◽

Donor Acceptor ◽

Si Doped ◽

P Type ◽

Mg Doped

AbstractWe report on results of low-temperature photoluminescence measurements performed on GaN films, grown by molecular beam epitaxy (MBE) on sapphire substrates. The GaN films are either Mg doped (p-type) or consist of a Mg-doped layer on top of a Si doped GaN layer (n-type). In the p-doped samples, the sharpness of the donor-acceptor-pair transition is striking, three phonon replicas are clearly resolved. A transition band occurs around 3.4 eV, which becomes dominant for samples with an np-layer structure. The position and the composition of the near band edge transitions are influenced by the growth of the buffer layers. Depending on the growth conditions a transition at 3.51 eV can be observed.

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Hole mobility in Mg-doped p-type InN films

Applied Physics Letters ◽

10.1063/1.2906374 ◽

2008 ◽

Vol 92 (13) ◽

pp. 132108 ◽

Cited By ~ 52

Author(s):

Xinqiang Wang ◽

Song-Bek Che ◽

Yoshihiro Ishitani ◽

Akihiko Yoshikawa

Keyword(s):

Hole Mobility ◽

P Type ◽

Mg Doped

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High p-type conduction in high-Al content Mg-doped AlGaN

Applied Physics Letters ◽

10.1063/1.4773594 ◽

2013 ◽

Vol 102 (1) ◽

pp. 012105 ◽

Cited By ~ 74

Author(s):

Toru Kinoshita ◽

Toshiyuki Obata ◽

Hiroyuki Yanagi ◽

Shin-ichiro Inoue

Keyword(s):

Al Content ◽

P Type ◽

High Al Content ◽

Type Conduction ◽

Mg Doped

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Mobility characterization of p-type and n-type strained sil-x-yGexcy/Si Epilayer hall devices

MRS Proceedings ◽

10.1557/proc-535-293 ◽

1998 ◽

Vol 535 ◽

Author(s):

Jeff J. Petersoa ◽

Charles E. Hunt ◽

Stefan F. Zappe ◽

Ernst Obeneier ◽

Richard Westhoff ◽

...

Keyword(s):

Doping Level ◽

Doping Concentration ◽

Impurity Scattering ◽

Temperature Range ◽

Boron Doped ◽

Ionized Impurity Scattering ◽

Van Der Pauw ◽

P Type

AbstractMobilities in Si1-x-yGex Cy layers were measured using mesa etched Van der Pauw structures for alloy layers with 0 < x < 0.30 and 0 < y < 0.02 and doping levels of 1015 < N < 1018 cm-3. Mobilities in Si1-x-yGex Cy layers with x = 0.27 were found to approach Si mobilities for both μn and μp.While electron mobilities in phosphorous-doped SiGeC decrease with doping concentration, hole mobilities in boron-doped SiGeC increase with doping level, indicating ionized impurity scattering is not dominant for μp over the temperature range studied.

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Ionized impurity scattering in heavily doped p-type InSb thin films

Thin Solid Films ◽

10.1016/0040-6090(79)90195-0 ◽

1979 ◽

Vol 60 (2) ◽

pp. 249-255 ◽

Cited By ~ 2

Author(s):

K.V. Krishna ◽

P.C. Mathur ◽

A.L. Dawar ◽

O.P. Taneja

Keyword(s):

Thin Films ◽

Impurity Scattering ◽

Ionized Impurity Scattering ◽

Insb Thin Films ◽

Heavily Doped ◽

P Type

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Doping Studies of n- and p-Type AlxGa1-xN Grown by ECR-Assisted MBE

MRS Proceedings ◽

10.1557/proc-449-233 ◽

1996 ◽

Vol 449 ◽

Cited By ~ 17

Author(s):

D. Korakakis ◽

H. M. Ng ◽

K. F. Ludwig ◽

T. D. Moustakas

Keyword(s):

Carrier Concentration ◽

Alloy Scattering ◽

Al Content ◽

Ecr Plasma ◽

Hall Effect Measurements ◽

Si Doped ◽

Long Range Ordering ◽

Power Measurements ◽

P Type ◽

Mg Doped

ABSTRACTAlxGal−xN films (x≤0.60) were grown on c-plane sapphire and (0001) 6H-SiC substrates using ECR plasma assisted Molecular Beam Epitaxy. Evidence of long range ordering in the investigated AlxGal−xN films is presented. Without intentional dopants the films are semi-insulating with resistivities ranging from 103 to 105 Ω.cm. The films were doped n-type with Si and p-type with Mg. The carrier concentration in the Si doped films, as determined by Hall effect measurements, was between 1016 to 1019 cm−3. At constant Si cell temperature, the carrier concentration was found to be reduced with AlN mole fraction, consistent with the observation that the donor ionization energy increases with Al content. Correspondingly, the electron mobility decreases with Al concentration, a result attributed to alloy scattering. The Mg doped films were found to exhibit p-type conductivity by thermoelectric power measurements with resistivities varying from 3 to 30 Ω-cm.

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P-type GaN epitaxial layers and AlGaN/GaN heterostructures with high hole concentration and mobility grown by HVPE

MRS Proceedings ◽

10.1557/proc-831-e8.28 ◽

2004 ◽

Vol 831 ◽

Cited By ~ 2

Author(s):

A. Usikov ◽

O. Kovalenkov ◽

V. Ivantsov ◽

V. Sukhoveev ◽

V. Dmitriev ◽

...

Keyword(s):

Hole Concentration ◽

Hole Mobility ◽

Hydride Vapor Phase Epitaxy ◽

Electrically Conducting ◽

Sapphire Substrates ◽

High Hole Concentration ◽

P Type ◽

Initial Results ◽

Mg Doped ◽

Effect Technique

ABSTRACTIn this paper we report p-GaN growth by hydride vapor phase epitaxy (HVPE) on sapphire substrates. Mg or Zn impurities were used for doping. Layer thickness ranged from 2 to 5 microns. For both impurities, as-grown GaN layers had p-type conductivity. Concentration NA-ND was varied from 1016 to 1018 cm−3. An annealing procedure at 750°C in argon ambient typically increased the concentration NA-ND in 1.5–3.5 times. For Mg doped GaN layers, room temperature hole mobility of 80 cm2V−1s−1 was measured by conventional Van Der Pau Hall effect technique for material having hole concentration of about 1x1018 cm−3. Initial results on highly electrically conducting p-type AlGaN/GaN heterostructures doped with Zn are also reported.

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Growth and Measurement of Mg Doped AlGaN/GaN Superlattice with Low Resistiviy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.549.274 ◽

2012 ◽

Vol 549 ◽

pp. 274-277

Author(s):

Jun Feng Chen

Keyword(s):

Al Content ◽

Superlattice Structure ◽

Annealing Conditions ◽

Great Progress ◽

Bulk Gan ◽

P Type ◽

Relationship Of ◽

The Relationship ◽

Mg Doped

Although the research of bulk GaN material has take great progress in recent years, while the high quality of p-type GaN material still is an obstacle to fabricate the HBT and LD devices. In this paper we growth a group of Mg doped AlGaN/GaN superlattices under variant conditions. The Hall, AFM, PL and HR-XRD measurement are taken to find the relationship of sample quality with the superlattice structure, growth and annealing conditions. The results show that the period length of about 9nm and Al content of 30% is the optimal structure; the best annealing temperature under tmosphere is about 540°C to 580°C. At last the p-type AlGaN/GaN superlattice with resistivity of 0.31Ω•cm is fabricated which can be utilize for the contact layers of blue LEDs.

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Highly p-Type a-GaN Grown on r-Plane Sapphire Substrate

MRS Proceedings ◽

10.1557/proc-0892-ff17-06 ◽

2005 ◽

Vol 892 ◽

Author(s):

Yosuke Tsuchiya ◽

Yoshizane Okadome ◽

Hiroko Furukawa ◽

Akira Honshio ◽

Yasuto Miyake ◽

...

Keyword(s):

Gas Flow ◽

Hole Concentration ◽

Hole Mobility ◽

Hall Effect Measurement ◽

Type A ◽

Temperature Dependent ◽

Type C ◽

Activation Ratio ◽

P Type ◽

Mg Doped

AbstractMg-doped p-type a-plane GaN films were grown on unintentionally doped a-plane GaN templates by metalorganic vapor phase epitaxy (MOVPE). The Mg concentration in a-plane GaN increased with increasing Mg source gas flow rate. A maximum hole concentration of 2.0 × 1018 cm-3 with a hole mobility of 4.5 cm2/Vs and resistivity of 0.7 Ω·cm were achieved. The activation ratio was 5.0 × 10-2. It was found that a maximum hole concentration in p-type a-plane GaN was higher than that in p-type c-plane GaN. The activation energy of Mg acceptors in p-type a-plane GaN with the maximum hole concentration was found to be 118 meV by temperature-dependent Hall-effect measurement.

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