Determination of potential distribution in a three-barrier structure

Model m₁-p-n-m₂ structures with three barriers were considered; construction and technology of manufacturing the three-barrier m₁-pAlGaInAs-nGaAs-m₂ structure are presented. Experimental methods to determine voltages across every junction of the three-barrier structure were proposed. The mechanism o...

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Опубліковано в: :Semiconductor Physics Quantum Electronics & Optoelectronics
Дата:2006
Автори: Yodgorova, D.M., Zoirova, L.X., Karimov, A.V.
Формат: Стаття
Мова:English
Опубліковано: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2006
Онлайн доступ:https://nasplib.isofts.kiev.ua/handle/123456789/121616
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Цитувати:Determination of potential distribution in a three-barrier structure / D.M. Yodgorova, L.X. Zoirova, A.V. Karimov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2006. — Т. 9, № 3. — С. 35-39. — Бібліогр.: 16 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-121616
record_format dspace
spelling Yodgorova, D.M.
Zoirova, L.X.
Karimov, A.V.
2017-06-15T03:06:36Z
2017-06-15T03:06:36Z
2006
Determination of potential distribution in a three-barrier structure / D.M. Yodgorova, L.X. Zoirova, A.V. Karimov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2006. — Т. 9, № 3. — С. 35-39. — Бібліогр.: 16 назв. — англ.
1560-8034
PACS 42.79.Pw, 68.55Ac
https://nasplib.isofts.kiev.ua/handle/123456789/121616
Model m₁-p-n-m₂ structures with three barriers were considered; construction and technology of manufacturing the three-barrier m₁-pAlGaInAs-nGaAs-m₂ structure are presented. Experimental methods to determine voltages across every junction of the three-barrier structure were proposed. The mechanism of current transport when changing the blocked p-n junctions and Schottky barriers were explained. It was shown that, at both polarities of operating regime, current characteristics are determined by blocked junctions. The obtained results are of interest for research of properties of three-barrier and similar phototransistor structures in response to external influences.
en
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
Semiconductor Physics Quantum Electronics & Optoelectronics
Determination of potential distribution in a three-barrier structure
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Determination of potential distribution in a three-barrier structure
spellingShingle Determination of potential distribution in a three-barrier structure
Yodgorova, D.M.
Zoirova, L.X.
Karimov, A.V.
title_short Determination of potential distribution in a three-barrier structure
title_full Determination of potential distribution in a three-barrier structure
title_fullStr Determination of potential distribution in a three-barrier structure
title_full_unstemmed Determination of potential distribution in a three-barrier structure
title_sort determination of potential distribution in a three-barrier structure
author Yodgorova, D.M.
Zoirova, L.X.
Karimov, A.V.
author_facet Yodgorova, D.M.
Zoirova, L.X.
Karimov, A.V.
publishDate 2006
language English
container_title Semiconductor Physics Quantum Electronics & Optoelectronics
publisher Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
format Article
description Model m₁-p-n-m₂ structures with three barriers were considered; construction and technology of manufacturing the three-barrier m₁-pAlGaInAs-nGaAs-m₂ structure are presented. Experimental methods to determine voltages across every junction of the three-barrier structure were proposed. The mechanism of current transport when changing the blocked p-n junctions and Schottky barriers were explained. It was shown that, at both polarities of operating regime, current characteristics are determined by blocked junctions. The obtained results are of interest for research of properties of three-barrier and similar phototransistor structures in response to external influences.
issn 1560-8034
url https://nasplib.isofts.kiev.ua/handle/123456789/121616
citation_txt Determination of potential distribution in a three-barrier structure / D.M. Yodgorova, L.X. Zoirova, A.V. Karimov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2006. — Т. 9, № 3. — С. 35-39. — Бібліогр.: 16 назв. — англ.
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AT zoirovalx determinationofpotentialdistributioninathreebarrierstructure
AT karimovav determinationofpotentialdistributioninathreebarrierstructure
first_indexed 2025-11-27T02:20:14Z
last_indexed 2025-11-27T02:20:14Z
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fulltext Semiconductor Physics, Quantum Electronics & Optoelectronics, 2006. V. 9, N 3. P. 35-39. © 2006, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine 35 PACS 42.79.Pw, 68.55Ac Determination of potential distribution in a three-barrier structure D.M. Yodgorova, L.X. Zoirova, A.V. Karimov Physical-Technical Institute of the Scientific Association "Physics-Sun" of the Academy of Sciences of the Republic of Uzbekistan, Mavlanov str., 2B, 700084, Tashkent Phone: +998-71-1331271, fax: +998-71-1354291; e-mail: karimov@uzsci.net Abstract. Model m1-p-n-m2 structures with three barriers were considered; construction and technology of manufacturing the three-barrier m1-pAlGaInAs-nGaAs-m2 structure are presented. Experimental methods to determine voltages across every junction of the three-barrier structure were proposed. The mechanism of current transport when changing the blocked p-n junctions and Schottky barriers were explained. It was shown that, at both polarities of operating regime, current characteristics are determined by blocked junctions. The obtained results are of interest for research of properties of three- barrier and similar phototransistor structures in response to external influences. Keywords: three-barrier structure, metal-semiconductor, p-n junction. Manuscript received 07.03.06; accepted for publication 23.10.06. 1. Introduction Nowdays, improvement of semiconductor device effectiveness is carried out in the technological process using several barriers. Then effectiveness of structures of solar cell type is improved using series connection of several cells switched in one direction with tunnel junctions between them in one cascade [1]. In the photodiode structure approaching, screw planar structures with two Shottky barriers are formed to improve their speed [2]. Existence of space charge layers near two barriers causes a decrease in the total capacity of the structure and as a result the speed increase takes place in them. In the diode structures, all processes are determined by a blocked junction due to one of the barriers is always switched in the opposite direction of the others, besides the voltage across the structure is determined as a whole by the blocked contact. That is why, their current-voltage characteristics (CVC) possess inverse brunches. Two-side sensitive two-barrier m-p-m, m-n-m structures with the Shottky barriers were described in [3]; owning to both rectifying metal-semiconductor junctions in them the photodetectors have high photosensitivity in the shortwaved spectral range when exciting them from any side. To improve photosensitivity and speed of the photodiode structure in the work [4], integration of p-n junction and reverse-based metal-semiconductor junctions into one aggregate structure was carried out. So, two-side sensitive two-barrier m-p-n [5, 6] and three-barrier m-p-n- m structures [7] were obtained. Their parameters depend essentially on technology of formation of active layers and potential barriers. Identity of CVC brunches was determined by perfection and correlation of carrier concentrations in regions forming the rectifying junction [8, 9]. Specimens of the above mentioned works had rather more high photosensitivity than an ordinar photodiode structure with one junction. In [10, 11], processes of photoelectric amplification and formation of spectral characteristics in three-barrier m1-pAlGaInAs- nGaAs-m2 structure were researched [12]. In operating regime when changing the applied voltage, they were redistributed between reverse-based barriers. The character of their redistribution and process of growth determines their photoelectric characteristics. Until recently theoretical [13] and experimental [14] approaches to researching the symmetrical m-n-m and nonsymmetrical two-barrier structures are known. In this work, described was redistribution of potential in symmetrical three-barrier hetero-m1- pAlGaInAs-nGaAs-m2-structures. 2. Experimental samples and methods of research To investigate the potential redistribution between barriers and determine the factors determining processes of current characteristics forming, special three-barrier heterostructures with symmetrical output characteristics were manufactured. nGaAs:O with the carrier concentration Nm = 1.1015 cm−3 was chosen as a substrate. Heterojunctions were obtained by growth of Zn-doped pAlGaInAs with Np = 2⋅1016 cm−3 on GaAs substrate. Thickness of the films was 2 to 3 μm. Then diode m1-p-n- m2 structure was formed depositing gold onto Semiconductor Physics, Quantum Electronics & Optoelectronics, 2006. V. 9, N 3. P. 35-39. © 2006, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine 36 -10 0 10 20 30 40 50 60 70 80 10-3 10-2 10-1 2 1 I, 10-6 А V, В 1 2 Fig. 2. Current-voltage characteristic of three-barrier m1-pAlGaInAs-nGaAs-m2 structure within the regimes of forward (1) and reverse (2) biases of heterojunction. pAl0.08Ga0.82In0.1As and silver with the thickness ~70 Å onto the back surface of nGaAs:O in vacuum. Here pm −1 1ϕ = 0.42 eV and 2 2 mn−ϕ = 0.88 eV for metal- semiconductor junctions pAl0.08Ga0.82In0.1As and nGaAs- Ag, accordingly. Heights of potential barriers ( pm −1 1ϕ and 2 2 mn−ϕ ) were determined from the dependence of square root of photoresponse, recalculated per one photon energy. That is in accordance with the data of [15]. The area of the structure was reduced to 5×5 mm by scribing. In the three-barrier structure, m1-p and n-m2 junctions were series-connected but p-n junction is approaching. This structure is two-side sensitive because both its surfaces are photodetectors, photocurrent is created by lighting any side. At forward bias of p-n junction, two metal- semiconductor junctions work within regime of reverse bias, moreover the current in circuit is limited only by the current of forward-biased metal-semiconductor junction with the bigger resistance. At reverse bias of p-n junction, a current is determined by blocked p-n junction and forward-biased metal-semiconductor junctions connected as one (Fig. 1). As shown in the equivalent scheme (Fig. 1), the resistances of the first and third junctions are Shottky barrier connected in series, and it is possible to consider them as one resistance 1 1R = 31 RR + , and the resistance of p-n junction as R2. From slops of curves for forward and reverse biases (Fig. 2) it is clear that the resistance 2 1 1 RR = , and three-barrier structure is symmetrical. We can determine the voltage across every junction from the data of CVC of Fig. 2 using the methods [14] for a two- barrier structure. We designate the voltage across R1 1 as V1 1 and R2 as V2. The sum of these voltages is the total voltage: .2 1 1tot 21 npmnpm VVV −−−− += (1) In their turn 21 31 1 1 mnpm VVV −− += , (2) n V1V2 p 1 Fig. 1. Simplified equivalent scheme of a three-barrier structure reduced to the two-barrier one. where pmV −1 1 and 2 3 mnV − are the voltages across m1-p and n-m2 junctions. Because of the equality of currents flowing through all the junctions: npnp RVVR −− = 2 1 12 1 1 , (3) then 1 1 1 12 2 R VR V np np − − = and (4) npV − 2 = 21 tot2 mnpmnp IR −−−− . (5) For the three-barrier m1-p-n-m2 system, assuming 21 31 1 12 mnpmnp RRRR −−− === as it is in symmetrical structure, we determine the resistance of the separate ( 2R or 1 1R ) junction in the point of contrary bend of CVC: 0 00 2 22 I VR R == , (6) where 0V , 0I are the voltage and current in the point of contrary bend, respectively. Resulting resistance of three p-n junctions connected in series is equal: R 0 = 0 0 I V . (7) Because [14] 21 tot 0 0 2 2 mnpmnp I I V V −−−− = (8) and npmnpm VVV −−−− −= 2tot 1 1 21 (9) on the base of the formulas (8) and (9) in the case of blocked metal-semiconductor junctions, we can calculate the voltages across npR − 2 and 1 1R junctions. When Semiconductor Physics, Quantum Electronics & Optoelectronics, 2006. V. 9, N 3. P. 35-39. © 2006, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine 37 changing the polarity of the applied voltage, the data for npR − 2 junction must be vary by the same way as for 1 1R one. In the case when the carrier concentrations in p and n regions are equal and the heights of metal- semiconductor potential barriers are equal, too, ϕ1 = ϕ2, we have V pm −1 1 = V 2 3 mn− , (10) V 1 1 = 2V pm −1 1 . (11) As a result, from the dependence (8) taking into account V pm −1 1 = V 1 1 /2, (12) we obtain formula for the voltage across the metal- semiconductor m-p junction 22 21 1 tot 0 0 1 mnpm pm I I V V −−− − = . (13) We also find expressions for the voltages V 1 1 = V pm −1 1 + V 2 3 mn− , (14) V 2 3 mn− = V 1 1− V pm −1 1 . (15) In the case when the heights of potential barriers are not equal ( 1ϕ ≠ 2ϕ ), voltages across them can be different, and there is certain correlation between their resistances pm mn R R − − 1 2 1 3 = 0 1 0 3 Е Е , (16) where 0 3Е is the electric field of m1-p junction, which is determined by relation of the potential barrier height to the thickness of the space charge layer [16] 2 1 2 2 10 30 3 30 3 2/ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ == − − n mn mn NqW E ϕεεϕϕ . (17) Here 0 1E is the electric field of m1-p junction, it is equal 2 1 1 2 10 10 1 10 1 2 / ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ == − − p pm mn NqW E ϕεε ϕ ϕ . (18) Within the regime of forward-biased p-n junction, taking into account (16)-(18) and solving the equations (2) and (18) pm mn V V − − 1 2 1 3 = 0 1 0 3 Е Е , (19) we obtain expression relating the voltage across the m1-p junction with the total voltage 0 3 0 1 0 11 )rev(1)rev(1 1 EE E VV pm + =− . (20) Here, 0 3 0 1 0 1 ЕЕ Е + is the coefficient describing relation of electrical fields between metal-semiconductor barriers connected in series, besides forw 0 3 0 1 0 1 ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ + ЕЕ Е = rev 0 3 0 1 0 1 ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ + ЕЕ Е (21) Using the formula (2), we determine the voltage across another n-m2 junction V 2 )rev(3 mn− = V1 )rev(1 − V pm −1 )rev(1 . (22) Within the blocked p-n junction regime, we find the voltage across the forward-biased m1-p junction by the same way V pm −1 )forw(1 = V1 )forw(1 . 0 3 0 1 0 1 ЕЕ Е + (23) and using the formula (23) we determine the voltages across the second forward-biased n-m2 junction V 2 )forw(3 mn− =V1 )forw(1 − V pm −1 )forw(1 . (24) Then, we find npV − 2 voltage across the blocked p-n junction V 1 )forw(1 m tot(rev))rev(2 21 VVV mnpnp −= −−−− . (25) So, we have the formulas to determine the voltages across every junction of the three-barrier structure. 3. Results and discussion In researching Au-pAl0.08Ga0.82In0.1As-nGaAs-Ag- structure, because of resemblance of CVC when varying the applied voltage, it is enough to estimate the applied voltages npV − 2 and V1 1 for only one of the regimes and then to replace the obtained values for the other regime. In the point of contrary bend at V = 5 V, I = 0.003 μA (Fig. 2). Then taking into account the calculated values of the coefficient and formula (12) and using the formulas (16), (17), (19), (21), we determine the voltages across the p-n heterojunction: npV − )forw(2 and 1 )rev(1V – across the metal-semiconductor series- connected junctions as well as V pm −1 1 and V 2 3 mn− – across the separate m1-p and n-m2 junctions. Within the forward-biased p-n heterojunction regi- me, we calculated values of the space charge layer thickness, electrical field intensity, capacities of blocked m1-p and n-m2 junctions using the formulas (26)-(29) 2 1 11 1 )(2 )rev(110 ⎟⎟ ⎟ ⎠ ⎞ ⎜⎜ ⎜ ⎝ ⎛ + = −− − p pmpm pm N V q W ϕεε , (26) Semiconductor Physics, Quantum Electronics & Optoelectronics, 2006. V. 9, N 3. P. 35-39. © 2006, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine 38 Table 1. Data of symmetrical Au-pAl0.08Ga0.82In0.1As-nGaAs-Ag structure within the forward-biased p-n heterojunction regime. 21 tot mnpmV −−− , V 2 5 10 15 20 30 40 70 21 tot mnpm I −−− , μA 0.001 0.003 0.006 0.008 0.010 0.014 0.017 0.025 npV − )forw(2 , V 1 3 6 8 10 14 17 25 1 )rev(1V , V 1 2 4 7 10 16 23 45 pmV −1 )rev(1 , V 0.758 1.56 3.0 5.3 7.58 12.12 17.43 34.1 pmW −1 , 10−5cm 2.72 3.53 4.64 6 7.1 8.89 10.6 14.7 E, 105 V/cm 0.43 0.56 0.74 0.95 1.13 1.41 1.67 2.35 С, 109 F 11.58 8.92 6.79 5.25 4.44 3.54 2.97 2.14 V 2 )rev(3 mn− , V 0.242 0.484 1.0 1.7 2.42 3.88 5.57 10.89 2mnW − ,10−5cm 8.53 10.37 14.3 19.6 25.1 36.2 49.02 89.5 E,105 V/cm 0.13 0.13 0.13 0.13 0.13 0.13 0.13 0.13 С, 10–9 F 2.85 2.4 1.7 1.24 0.97 0.67 0.49 0.28 Table 2. Data of symmetrical Au-pAl0.08Ga0.82In0.1As-nGaAs-Ag structure within the reverse-biased p-n heterojunction regime. 21 tot mnpmV −−− , V 2 5 10 15 20 30 40 70 21 tot mnpm I −−− , μA 0.001 0.003 0.006 0.008 0.010 0.014 0.017 0.025 V 1 )forw(1 , V 1 3 6 8 10 14 17 25 pmV −1 )forw(1 , V 0.758 2.27 4.55 6.06 7.58 10.61 12.88 18.95 V 2 )forw(3 mn− , V 0.242 0.73 1.45 1.94 2.42 3.39 4.12 6.05 V np− )rev(2 , V 1 2 4 7 10 16 23 45 npW − ,10−5cm 16.46 20.08 25.8 32.6 38.2 47.45 56.36 77.98 E,105 V/cm 0.12 0.15 0.196 0.25 0.29 0.36 0.43 0.59 С, 10–9 F 1.91 1.57 1.22 0.97 0.82 0.66 0.56 0.40 2 1 22 2 )rev(310 (2 ⎟⎟ ⎟ ⎠ ⎞ ⎜⎜ ⎜ ⎝ ⎛ + = −− − n mnmn mn N V q W ϕεε . (27) Capacity and electrical field intensities for every junction were calculated on the base of these space charge layer thickness values by using the formulas W S C 0εε = , (28) W VE = . (29) Within the reverse-biased heterojunction regime, we calculated the value of the p-n junction space charge layer thickness [13] ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ ⋅+⋅ −⋅+⋅ = − − pnpn np Dnp np NNNNq VVNN W )( )()(2 0201 2 2 02012 εεεε εεεε , (30) where E1 = 11.4 for Al0.08Ga0.82In0.1As and E2 = 11 for GaAs; VD = 1.054 V. Electrical field intensities and blocked p-n heterojunction capacity were calculated using the formulas (36), (37). The calculated data are summarized in Tables 1 and 2. Interconnection between index of CVC, carrier concentration, space charge layer thickness, dielectrical permittivity, capacity and electrical fields of junctions are ascertained on the base of the data shown in Tables 1 and 2. 4. Conclusion Considered are the model m2-p-n-m2 structures with three barriers, given are construction and manufacturing technology of three-barrier structure on the base of gallium arsenide. Proposed is the experimental calcu- lation method to determine voltages that drop on each transitions of the three-barrier structure. Obtained results can be applied for research the properties of three-barrier and analogical phototransistors under external affect. Semiconductor Physics, Quantum Electronics & Optoelectronics, 2006. V. 9, N 3. P. 35-39. © 2006, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine 39 References 1. J.I. Alferov, V.M. Andreyev, V.D. Rumyantcev, Tendency and perspective of solar photoenergetics development // Fizika, tekhnika poluprovodnikov 38(8), p. 937-947 (2004) (in Russian). 2. S.V. Averin, Determination of contact characteristics of metal-semiconductor for counter- pintle photodiode structure // Pis’ma in ZhTF 16(4), p. 49-53 (1990) (in Russian). 3. D.M. Yodgorova, E.N. 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