Switching Delay of Avalanche S-diodes in Circuit with Optical Drive

I.A. Prudaev, M.S. Skakunov, O.P. Tolbanov, S.S. Khludkov, and K.M. Degtyarenko.

Abstract—The results of study of avalanche S-diodes in circuit with pulse optical drive are presented. Experimental dependences of delay time of S-diodes switch on laser energy with wave-length 0.78 mkm are presented. It is shown that switching delay of avalanche S-diodes caused by recharging of deep traps in space charge region

Index Terms—Gallium arsenide, deep centers, space charge region, avalanche S-diode, switching delay, relaxation oscillator circuit



he avalanche S-diodes are used in the pulse power supply of various electronic devices [1]. The time of S-diode switch does not exceed 1 ns; voltage of switch is to 1000 V; pulse current is to 50 A. The S-diodes are manufactured on the basis of π-ν-nstructures which aremadeby doping of n-GaAs with deep acceptors. The mechanism of S-diode switch is associated with recharging of deep acceptors in π-ν-junction at microplasma avalanche breakdown conditions. The structures have light sensitivity in the infrared range what allows to use S-diodes in optoelectronic devices [2]. There is no information about pulse optical drive of avalanche S-diodes in the literature. Therefore in present study we analyze dependence of switching delay of S-diodes as a function of optical pulse energy. Mechanism of delay origin is discussed.


The technique of diode sample manufacturing is described in detail in [3,4]. For optical experiments it was made packageless diodes.

The dependences of delay time on pulse optical energy were measured. Triggering was made by single optical signals with the wave length 0.72 mkm. We used relaxation oscillator circuit based on S-diode [1]. Continuous voltage drop was less than voltage of switch but sufficient for microplasma avalanche breakdown of the S-diodes (this process is accompanied by exponential increase of current with voltage increase). At illumination condition S-diodes switched on during delay time and own time of switch (own time did not exceed 0.5 ns). After switch capacity was discharged leading to rise of electrical signal at the load resistance. The delay time is the time between rise-up portion of triggering signal measured by photodiode and rise-up portion of signal at theload resistance ofrelaxation oscillator circuit.

As the capacity we used coaxial line with impedance 50 Ohm. The measurements were made using Keithley 2410 source-meter and LeCroy 104 Xsoscilloscope. The operating time of silicon photodiode is 2 ns. As the light source we used infrared laser with wave-length 0,78 mkm. Themeasurements of optical energy were made using Gentec-e ED-100A UV.


At the Fig.1 typical dependences of delay time on pulse optical energy are shown. As energy increase the delay time decrease. Earlier it was shown that in peaking circuit delay time is caused by recharging of deep acceptors in π-ν-junction and can be associated with relationship [2,5]:


were td – delay time, σp - capture cross-section of holes on deep acceptors, VS–saturation velocity of the holes in space charge region (SCR), and p – hole concentration which is summed up of photo-carriers (pPh) and avalanche carriers (pAv). Therefore equation (1) can be written as:


The function f(U) do not depended on absorbed light energy (Eab). The dependence of f(U) on the voltage U is complicatedbecause of microplasma nature of breakdown.

To derive the equation for pPh(Eab) we took into account that a portion of light were reflected by diode surface. Then


were Np – number oh photo-holes, V – volume of photon absorption, NPh – number of photons, η – quantum efficiency, hν – energy of photons.

Assuming that area of light spot do not equal to area of S-diode active region (Eab = K∙E, E – measured pulse energy and K ≈ 5∙10-3 is coefficient)we derived final equation for analysis


It is appears from equation (4) than in coordinate 1/td and E the dependence is linear what is in agreement with our experimental results (Fig.2). With known values σp = 1015 cm-3, VS = 107 cm/c [6,7], V ≈ 15.32∙103 mkm3 (at hν = 1.59 eV thickness of light absorption in GaAs is 2.5 mkm [8]) slope ratio is γ ≈ 1.28∙1016∙η (J∙s)-1. Calculation of quantum efficiency from experiment (Fig.2) gives η ≈ 4.69∙10-4 which is acceptable value for actual geometry of S-diode.


Experimentally obtained dependences of delay time on pulse optical energy for the avalanche S-diodes are described by td~ E-1. The analysis of results has shown thatmechanismof switching delay in circuit with the optical drive is explained by recharging of deep acceptors in the space charge region.


Authors thank Prof. Gaman V.I. (TomskStateUniversity, Tomsk) for interest in work and fruitful discussionof the results.


[1]Ilyushenko, V.N., Picosekundnaya impul’snaya tehnika,Moscow,1993.

[2]D. D. Karimbaev, A.V. Koretskii, Yu.D. Pavlov, et al., “Razrabotka GaAs diodov i ih primenenie v impul’snoy tehnike,” Electron. Prom., no. 9, 1993, pp. 62-70.

[3]I.A. Prudaev, S.S. Khludkov, M.S. Skakunov, O.P. Tolbanov, “Pereklyuchayushiye lavinnye S-diody yna osnove GaAs mnogosloynyh structur,” Prib. Tekh. Eksp., no. 4, 2010, pp. 68-73 [Instrum. Exp. Tekh. (Engl. Transl.), 2009, no. 2, p. 212].

[4]I.A. Prudaev, S.S. Khludkov, “Vliyaniye tolshiny bazy lavinnogo S-dioda na ego oratnuyu vol’t-ampernuyu haracteristiku,” Izv. Vyssh. Uchebn. Zaved., no. 11, 2009, pp. 48-53.

[5]P. Yu. Beloborodov, O. P. Tolbanov, S. S. Khludkov, “Vliyaniye protzessov perezaryadki glubokih tzentrov na zaderzhru proboya arsenid-gallievyh struktur, kompensirovannyh zhelezom,” Fiz. Tekh. Poluprovodn. (St. Petersburg), no. 4, 1988, pp. 755-757.

[6]Sze, S.M., Physics of Semiconductor Devices, New York: Wiley, 1969.

[7]S.S. Khludkov, O.P. Tolbanov, V.G. Lahtikova, “Issledovaniye chastotnoy I temperaturnoy zavisimostey baryernoy yomkosti p-n-perehodov v arsenide galliya, soderzhashih glubokiye tzentry , i opredeleniye parametrov glubokih tzentrov,” Radiotehn. I electron. no. 9, 1973, pp. 1893-1899.

[8]Kesamanly, F. P. Arsenydgalliya. Polucheniye i primeneniye. Мoscow, 1973.

Manuscript received May 6, 2011. This work was supported in part by The Minestry of Science and Education of Russian Federation under Grants No.16.740.11.0231, No.2.1.2/12752, and No.П866).

I. A. Prudaev is with TomskStateUniversity, Tomsk, Lenina 36, Russia (phone: +7(3822)413828; fax: +7(3822)412588; e-mail: ).

M. S. Skakunov is withTomskStateUniversity, Tomsk, Lenina 36, Russia (e-mail: ).

O. P. Tolbanov is with TomskStateUniversity, Tomsk, Lenina 36, Russia(e-mail: ).

S. S. Khludkov is withTomskStateUniversity, Tomsk, Lenina 36, Russia (e-mail: ).

K. M. Degtyarenko is with TomskStateUniversity, Tomsk, Lenina 36, Russia (e-mail: ).