Ultrahigh Be doping of Ga0.47In0.53As by low-temperature molecular beam epitaxy

Hamm, R. A.; Panish, M. B.; Nottenburg, R.N.; Chen, Y. K.; Humphrey, D.A.

doi:10.1063/1.101057

Cited by 70 publications

(6 citation statements)

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“…In the nonequilibrium case, raised doping concentrations 10 20 cm ÿ3 have been achieved by epitaxial methods in Si 1ÿx Ge x :B [1][2][3], GaAs:N [4], GaInAs:Be [5], GaAs:C [6], and C in diamond [7]. Even higher, still electrically active, doping concentrations of up to 10 22 cm ÿ3 have been achieved in localized layers by so called -doping [8][9][10].…”

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confidence: 99%

Increasing the Equilibrium Solubility of Dopants in Semiconductor Multilayers and Alloys

et al. 2008

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We have theoretically studied the possibility to control the equilibrium solubility of dopants in semiconductor alloys, by strategic tuning of the alloy concentration. From the modeled cases of C 0 in Si x Ge 1ÿx , Zn ÿ and Cd ÿ in Ga x In 1ÿx P it is seen that under certain conditions the dopant solubility can be orders of magnitude higher in an alloy or multilayer than in either of the elements of the alloy. This is found to be due to the solubility's strong dependence on the lattice constant for size mismatched dopants. The equilibrium doping concentration in alloys or multilayers could therefore be increased significantly. More specifically, Zn ÿ in a Ga x In 1ÿx P multilayer is found to have a maximum solubility for x 0:9, which is 5 orders of magnitude larger than that of pure InP. [8][9][10]. From a theoretical point of view the raised nonequilibrium concentrations have been successfully explained by the increased range of the chemical potential of the dopant during epitaxial growth [11][12][13].In this Letter we consider ways to increase the solid solubility to achieve higher doping concentrations under equilibrium conditions. We study the dependence of the equilibrium solubility of substitutional defects, including dopants, in compound semiconductors A x B 1ÿx . We demonstrate that the equilibrium solubility of dopants need not be monotonic in x and lie between those of the pure materials A and B. Instead, we will show that careful tuning of x can result in equilibrium solubilities many orders of magnitude higher in the alloy than in either of the pure materials.It is well known that high doping can alter the lattice constant of a material [14]. Here we investigate the possibility of using changes in the lattice constant to control the doping concentration. Initial indications of this have been noted in previous experimental work [15], in theoretical studies of dopants in silicon under applied biaxial strain [16] and for vacancies and self-interstitials using a phenomenological method [17]. However, the full implications of this possibility have not so far been realized.Our hypothesis builds on the way in which the solubility depends on the difference between the dopant's and the substituted host atom's equilibrium bond lengths. The solubility of a dopant atom of the same size and equilibrium bonding distance as the host atoms will have little dependence on the strain of the material since the difference in bond energy will be constant. If the equilibrium bonding distances differ, however, the solubility of the dopant may have a strong dependence on the lattice constant, such that the equilibrium solubility of smaller (larger) dopants increases under compressive (expansive) strain. Our results show for the first time that the equilibrium concentration of a defect can sometimes be orders of magnitude higher in an alloy or multilayer than in either of the constituents. This leads to the possibility of increasing the equilibrium solubilities of dopants through strategically composing multilayers or alloys...

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confidence: 99%

Increasing the Equilibrium Solubility of Dopants in Semiconductor Multilayers and Alloys

et al. 2008

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“…Substrate temperatures (T s ) were measured using a thermocouple inserted into an In-filled well in the back of the a͒ Electronic mail: hkuo@filss.com Mo block in a manner similar to that reported by Hamm et al The thermocouple was calibrated by observing the melting point 525°C of InSb. 14 All of the samples were grown on epiready InP ͑100͒ semi-insulating substrates with the growth temperature 470°C and the growth rates of 1 and 0.55 m/h for InGaAs and InP, respectively. The npn HBT structure consists of: a 5000 Å n ϩ -InP subcollector (1ϫ10 19 cm Ϫ3 ), an n Ϫ InGaAs ͑4000 Å͒ collector, a 700 Å carbon doped base (4 ϫ10 19 cm Ϫ3 ), a 1000 Å InP emitter layer (8ϫ10 17 cm Ϫ3 ), and a 1500 Å n ϩ -InGaAs emitter contact layer (1 ϫ10 19 cm Ϫ3 ).…”

Section: Methodsmentioning

confidence: 99%

Growth of carbon doping Ga0.47In0.53As using CBr4 by gas source molecular beam epitaxy for InP/InGaAs heterojunction bipolar transistor applications

Kuo

Ahmari

Moser

et al. 1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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In this article, we present the comparison of material quality and device performance of gas-source molecular beam epitaxy (GSMBE)- and metal-organic molecular beam epitaxy (MOMBE)-grown C-doped InGaAs and npn InGaAs/InP heterojunction bipolar transistors (HBTs). The results indicate that the crystal quality of GSMBE-grown samples is comparable to that of MOMBE-grown samples. The GSMBE-grown HBTs show excellent dc and high frequency performance. The dc current gain (β) was 37 at a collector current of 21 mA and the emitter-base and base-collector junction ideality factors were 1.14 and 1.04 indicating good junction properties. For high frequency performance, the fT and fmax are around 108 and 128 GHz for a 4000 Å InGaAs collector with an emitter area of 3×10 μm2. Finally, the thermal stability of C-doped InGaAs and its effects on InP/InGaAs HBT device reliability will be discussed.

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“…Beryllium ͑Be͒ is a widely used p-type dopant in ultrahigh vacuum systems like molecular beam epitaxy ͑MBE͒ and metalorganic MBE or chemical beam epitaxy ͑MOMBE/ CBE͒ due to its large sticking coefficient at usual growth temperatures. 1 Even though extremely high Be doping ͑Ͼ10 20 cm Ϫ3 ͒ has been achieved for InGaAs by several authors, [2][3][4] high Be doping in InP has shown to be difficult both due to the lower solid solubility of Be in InP 5 and to surface degradation. 6,7 We show here a study on the growth mechanisms leading eventually to the observed surface degradation using x-ray diffraction ͑XRD͒, atomic force microscopy ͑AFM͒, Auger and secondary ion mass spectrometry ͑SIMS͒.…”

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“…We can observe that for the lower T Be , the slope of the curve follows that of the Be vapor pressure. 2,8 At the highest T Be , however, a saturation in the electrical activation of the dopant is reached. The maximum carrier concentration ͑ϳ2ϫ10 18 cm Ϫ3 in our case͒ does not change for the growth temperatures considered here.…”

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“…Similar saturation in the dopant electrical activation and the dependence of maximum carrier concentration on growth temperature have been reported for Be doping of both InP and InGaAs. 2,9 Figure 2 shows Nomarski pictures of InP surfaces of doped and undoped samples grown at T g ϭ530°C. The change in surface morphology is quite obvious even at such low magnification scale.…”

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Be incorporation and surface morphologies in homoepitaxial InP films

Cotta

Carvalho

Pudenzi

et al. 1995

Applied Physics Letters

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We have studied the mechanism of Be incorporation in InP homoepitaxial films grown by metalorganic molecular beam epitaxy. The actual Be concentration in the films reaches 1–2×1019 cm−3 while the hole concentration saturates at a lower value ■∼2×1018 cm−3 in our case). The measured lattice mismatch between film and substrate depends both on growth temperature and Be flux. The resulting changes in morphology suggest that the excess Be forms microclusters in the films grown at higher temperatures—due to the higher surface mobility, leading to the growth of oval defects. Be rejection to the surface is also observed. The surfaces of samples with no cap layer present a granulation which may be related to the formation of a new phase like Be3P2.

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Ultrahigh Be doping of Ga0.47In0.53As by low-temperature molecular beam epitaxy

Cited by 70 publications

References 8 publications

Increasing the Equilibrium Solubility of Dopants in Semiconductor Multilayers and Alloys

Increasing the Equilibrium Solubility of Dopants in Semiconductor Multilayers and Alloys

Growth of carbon doping Ga0.47In0.53As using CBr4 by gas source molecular beam epitaxy for InP/InGaAs heterojunction bipolar transistor applications

Be incorporation and surface morphologies in homoepitaxial InP films

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