AlGaN/GaN. , p-i-n. PACS: Fd, Bt, Gz. GaN,. , n AlGaN/GaN. . AlGaN/GaN. (high electron mobility transistor, HEMT)

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1 AlGaN/GaN p-i-n * (, ) ( ; ), Poisson-Schrödinger, p-algan AlGaN/GaN p-i-n., p-algan.,, p-algan, p-algan, i-gan,.,, p-algan,.. : AlGaN/GaN,, p-i-n, PACS: Fd, Bt, Gz 1 GaN,,. [1]., [2]., [3,4], [5,6]., p-i-n., AlGaN Al, ev,,,. AlGaN/GaN p-i-n, AlGaN, GaN,., AlGaN/GaN,, [7]. AlGaN/GaN,, n AlGaN/GaN (high electron mobility transistor, HEMT) [8],., AlGaN/GaN p-i-n [9],. AlGaN/GaN,, p-algan AlGaN/GaN p-i-n * ( : , ) ( : ) ( : ). hxliu@mail.xidian.edu.cn c 2012 Chinese Physical Society

2 [3,10,11] AlN GaN InN Acta Phys. Sin. Vol. 61, No. 5 (2012) ;,. 2 AlGaN/GaN p-i-n,.,, GaN InN AlN, 1. P pe (AlGaN)], (4), r,,. r 0, AlGaN/GaN ; r 1, AlGaN/GaN. 1 AlGaN/GaN p-i-n.,, 1 δ. p-i-n, 2. Al x Ga 1 x N, x = P sp/c.m a 0 / e 31 /C.m e 33 /C.m C 13 /GPa C 33 /GPa AlGaN/GaN p-i-n 1, P sp, a 0, e 31 e 33, C 13 C 33. Al x Ga 1 x N GaN AlN,, (1) (2) [10] : P sp Al x Ga 1 x N = P sp AlN x + P sp GaN (1 x), (1) P pe = 2 a a [ 0 C ] 13 e 31 e 33. (2) a 0 C 33, AlGaN/GaN σ,, (3) : σ = P sp (GaN) P sp (AlGaN) P pe (AlGaN). (3), AlGaN/GaN Al, [10 12].. Al, AlGaN/GaN (4) : σ = r[p sp (GaN) P sp (AlGaN) 2 p-i-n (x = 0.2) /nm /cm 3 p Al xga 1 x N δ Al xga 1 x N ( ) i GaN n GaN δ, δ,.,.,,. (5) : δn = Q V = Q S L = σ L, (5), Q, V, S, L, σ. x = 0.2, (1), (2), (4) (5), cm 2. δ

3 , 1 nm, δ δn = σ/l = cm 3. 3, Al- GaN/GaN,., Al- GaN/GaN p-i-n Poisson-Schrödinger. Schrödinger 2 d [ 1 d ] 2 dz m (z) dz ψ(z) + E c (z)ψ(z) = Eψ(z), (6), Planck, m, z, ψ, E, E c. E c (7) : E c (z) = qv (z) + Ec(z), (7), q, V, E c. AlGaN/GaN, Ec = 0.63 E g, E g. AlGaN AlN GaN, (8) : E g (x) = 6.28x (1 x) x(1 x). (8) Schrödinger (6), E i ψ i, n s2d (z) n 2D (z), (9) (10) : n s2d = i = i n 2D (z) = i n i m 1 π 2 E i 1 + exp( E E (9) F )de, k 0 T n i ψ i (z)ψ i (z), (10), E i i, n i i m, π 2, E F Fermi, k 0 Boltzmann, T, Fermi-Dirac, ψ i (z) E i z., Schrödinger., Poisson, (7). Al- GaN/GaN,, Poisson d [ε 0 ε r (z) d ] dz dz V (z) = ρ(z), (11), ρ(z) = q[n + D N A +p n+p 2D n 2D +δn], (12), ε r, ε 0, N + D, N A, p n, δn. Poisson-Schrödinger. GaN [13] [14], AlGaN/GaN p-i-n : p(z) = G(z) U p (z) 1 J p (z), t q z (13) n(z) = G(z) U n (z) + 1 J n (z), t q z (14), p(z), n(z) ; G(z), U(z) ; J p (z), J n (z)., J p (zx) J n (z) (15) (16) : J p (z) = qp(z)µ p E qd p dp(z) dz, (15) J n (z) = qn(z)µ n E + qd n dn(z) dz, (16) µ p, µ n ; D p, D n, E. G(z) U(z) (17) (19) : G(z) = P opt(1 R) α exp( αz), A hc/λ (17) U p (z) = p(z), τ p (18) U n (z) = n(z) τ n, (19) P opt, R, A, h Planck, λ

4 , c, α GaN, τ p, τ n., cm 2. [15,16]. p-algan, i-gan., p-algan i-gan. 4, AlGaN/GaN p-i-n,, p-algan 2 p-algan (a) ; (b) 2 p-algan. 2,, p-algan cm cm 3, p-algan, i-gan. p-algan,, p-algan, 3 p-algan., p-algan,. GaN. GaN, 220 kv/cm,,., p-algan,,.,, p-algan, p-algan, i-gan,,. 4, r, (4), p- AlGaN cm 3., AlGaN/GaN, Al,., , r 1 0.1, p-algan, i-gan,.,,,, i-gan.,,,,

5 , i-gan. i-gan,,., p-algan,, p-algan,,. 6 GaN p-i-n., 200 K 400 K,,., AlGaN/GaN p-i-n. 6 p-i-n 4 (a) r = 1.0; (b) r = 0.7; (c) r = 0.4; (d) r = ,., AlGaN/GaN,,. p-algan,, δ, p-algan Al- GaN/GaN p-i-n. : p-algan, p-algan, i-gan. p-algan. p-i-n,. p-algan,.,, p-i-n., AlGaN/GaN p-i-n. 200 K 400 K,,,

6 [1] Marso M 2010 IEEE Conference on Advanced Semiconductor Device & Microsystems 147 [2] Unil A G, Jayasinghe R C 2009 IEEE Nanotechnology Materials and Devices Conference 142 [3] Ambacher O, Smart J, Shealy J R, Weimann N G, Chu K, Murphy M, Schaff W J, Eastman L F 1999 Appl. Phys [4] Ambacher O, Smart J, Shealy R J 2002 Appl. Phys. Lett [5] Pereiro J, Rivera C 2009 IEEE J. Quantum Electronics [6] Ulker E, Yelboga T, Turhan B 2009 IEEE LEOS Annual Meeting Conference 235 [7] Khan A, Yang J W 2002 Int. J. High Speed Electronics and Systems [8] Ma X H, Pan C Y, Yang L Y, Yu H Y, Yang L, Quan S, Wang H, Zhang J C, Hao Y 2011 Chin. Phys. B [9] Zhou J J, Jiang R L, Ji X L, Xie Z L, Han P, Zhang R, Zheng Y D 2007 Chin. J. Semiconduct (in Chinese) [,,,,,, ] [10] Ambacher O, Foutz B, Smart J, Shealy J R, Weimann N G, Chu K, Murpphy M, Slerakowski A J, Schaff W J, Eastman L F 2000 J. Appl. Phys [11] Bernardini F, Fiorentini V, Vanderbilt D 1997 Phys. Rev. B 56 R10024 [12] Ozgur A, Kim W 1995 Electron Lett [13] Maziar F, Carlo G, Enrico B, Kevin F B, Michele G, Enrico G, Giovanni G, John D A, Ruden P P 2001 IEEE Trans. Electron Devi [14] Pulfrey D L, Nener B D 1998 Solid-State Electron [15] Gao B, Liu H X, Wang S L 2011 Chin. Phys. Lett [16] Kolbe T, Knauer A, Chua C 2010 Appl. Phys. Lett

7 Influence of polarization effects on photoelectric response of AlGaN/GaN heterojunction p-i-n photodetectors Liu Hong-Xia Gao Bo Zhuo Qing-Qing Wang Yong-Huai ( Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices of the Ministry of Education, School of Microelectronics, Xidian University, Xi an , China ) ( Received 16 March 2011; revised manuscript received 12 May 2011 ) Abstract Based on the simulation of the polarization effect by the sheet charge layer approximately, the energy band structures and electric field distributions of AlGaN/GaN heterostructures with different doping concentrations of p-algan and polarization effects are calculated by self-consistenly solving the Poisson-Schrödinger equations. The corresponding photoelectric response is calculated and discussed by solving the carriers continuity equation. The results show the interaction between the doping concentration and the polarization effect has an important influence on the performance of the p-i-n detector. Specially, under the condition of complete polarization, a high doping concentration in the p-algan layer will result in a narrow depletion region in p-algan layer and the i-gan layer will be depleted easily, which corresponds to a low photocurrent. Similarly, a strong polarization will result in a wide depletion region in p-algan and high photocurrent for the same doping concentration in p-algan layer. Finally, the effect of temperature on the performance of the detector is calculated and analyzed. It is concluded that AlGaN/GaN heterostructure p-i-n ultraviolet detector can be used in the high temperature environment. Keywords: AlGaN/GaN heterojunction, photodetectors, p-i-n structure, polarization effect PACS: Fd, Bt, Gz * Project supported by the National Natural Science Foundation of China (Grant Nos , ), Cultivation Fund of the Key Scientific and Technical Innovation Project, Ministry of Education of China (Grant No ), and the Defense Research Foundation of Microelectronics, China (Grant No ). hxliu@mail.xidian.edu.cn