Silicon carbide dynistor

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A. M. Zaitsev for assistance in this study. 1v. A. Dmitriev, P. A. Ivanov, I. V. Korkin, Ya. V. Horozenko,. I. V. Popov, T. A. Sidorova, A. H. Strel'chuk, and V. E. Chel-.
Silicon carbide dynistor

351

Silicon carbide dynistor S. N. Vainshtein, V. A. Dmitriev, A. L. Syrkin, and V. E. Cnelnokov A. F. Joffe Physicotechnica/ Institute, Academy ofSciences of the USSR. Leningrad

(Submitted June I, 1987) Pis'ma Zh. Tekh. Fiz. 13, 991-993 (August 26, 1987)

The crystallization of silicon carbide layers from a solution of carbon in molten silicon 1 has made It possible to fabricate structures with a single p-n junction for diodes and stabilitrons, 2 tunnel diodes, 3 and field -effect transistors. 4 We showed in Ref. 5 that silicon carbide structures with several p-n junctions can be grown from the liquid phase in a single process. In this letter we are reporting the fabrication of silicon carbide p-n-p-n dynistor structures by the technique of Ref. 5. A structure consisting of three layers, n-p-n+, is grown in a series of steps in a single technological process on a p+-SiC(6H) substrate. Aluminum is added to the molten solution to produce p-SiC; the donor impurity is qitrogen.

where U0 n ., 2.8 V. The resistance is Rg ., 100 n (the reduced resistance is -2·10-2 n·cm2); i.e., the voltage-current characteristic of the dynistor in the open state corresponds to the characteristic of a forward-biased silicon carbide diode. 2 The reverse branch of the voltage-current characteristic contains a region of abrupt breakdown, at voltages Ubreak 60-85 V. At U 5 0.9 Ubreak• the reverse current through the structure does not exceed -10- 6 A. In the operation of the p-n-p-n structures in the open state, we observe a blue-violet electroluminescence, which is characteristic of SiC(6H) lightemitting diodes made from a Si-C molten solution.6 Visual observation from the side of the mesa structure (after the partial removal of the aluminum con-

The contacts are deposited, an the mesa structures are fabricated, by the methods used for SiC diodes. 2 Aluminum is used as the material for making contact to the n+-siC and the p+-siC. The size of the mesa structures is 150 x 150 IJITI (s ' ., 2 ·1o-• cm2). The p-n-p-n structures which were grown have a typical dynistor voltage-current characteristic. Measurements were carried out with direct current at room temperature. The static connection voltage of the silicon carbide structures, Us, lies in

the rangfl 10-50 V (Fig. 1).

The. switc-:h to

th~

.• +·to p·SiC

.,...> !0~1~,-+~~4-~+-~

II

op(ln

state occurs when the current through the structure is 0. 2-4 rnA. In the open state, with currents up to 100 rnA, the voltage-current characteristic of the dynistor is approximately linear: I = (U - U0 n)/Rg,

0 Zi: Y/div FIG. l.

Voltage-current characteristic of a silicon carbide

dynistor.

Reprinted from Soviet Technical Physics Letters 13,413-414 ( 1987);@ American Institute of Physics.

352

Other Semiconductor Devices

tact from the n+ layer) revealed that the size of the emitting region increases with an increase in the current flowing through the structure. That is, we ohRorvo n propnv,ntion of tho "on" Rlntn within ttw area of the mesa structure. The entire area of the sample is turned on at currents of 60-70 rnA (j " 300 A/cm2). The dynistors are turned on by virtue of the dU/dt effect by square voltage pulses with a rise time -300 ps and U 0 « Us. On the curve of the current through the dynistor versus the time we observe a turn-on delay which is typical of p-n-p-n structure and which decreases with increasing amplitude U 0 • Preliminary measurements showed that the current rise time during the turn-on of the dynis tor, as determined from the criterion ( 0. 1-0. 9) · I max, does not exceed 70 ns. The time required for the restoration of the blocking properties of the dynistor at a current density j - 103 A/cm2 through the structure is t 0 ff 2: 200 ns.

nokov, Pis'ma Zh. Tekh. Fiz. 11. 238 (1985) [Sov. Tech. Phys. Lett. 11, 98 (1985}]. 2V. A. Dmitriev, P. A. Ivanov, I. V. Popov, A. H. Strel'chuk, A. I.. Syrkin, and V. E. r.helnokov, Pls'JM Zh. Tekh. Fir. . U. 773 (1986) [Sov. Tech. Phys. Lett . 11, 318 (1986)] . 3 v. A. Dmitriev, P. A. Ivanov, A. M. Strel'chuk, A. L. Syrkin, I . V. Popov, and V. E. Che1nokov, Pis'ma Zh. Tekh. Fiz. 11, 976 (1985) [Sov. Tech. Phys Lett. ll., 403 (1985}]. ~.H. Anikin, V. A. Dmitriev, P. A. Ivanov, - A. A. Lebedev, Ya. V. Morozenko, I. V. Popov, A, M. Stre 1' chuk, A. V. Suvorov, A. L. Syrkin, and V. E. Chelnokov, in: Proceedings of the Third All-Union Conference on the Physics and Technology of Wide-Gap Semiconductors, Hakhachkala, September 10-12, 1986 (in Russian], Hakhachkala, pp. 97-98 . 5v. A. Dmitriev, I. V. Popov, and V. E. Chelnokov, in: Proceedings of the Third Conference on the Growth and Synthesis of Semiconductor Crystals and Films, June 9-13, 1986 (in Russian], Vol. l, Novosibirsk, pp. 51-52. 6v. A. Dmitriev, P, A. Ivanov, Ya. V. Horozenko, I. V. Popov, and V. E. Chelnokov, Pis'ma Zh. Tekh . Fiz. 11, 246 (1985} (Sov . Tech. Phys. Lett. 11, 101 (1985)].

We are deeply ind,ebted to I. D. Kovalenko and A. M. Zaitsev for assistance in this study. 1v. A. Dmitriev, P. A. Ivanov, I. V. Korkin, Ya. V. Horozenko, I. V. Popov, T. A. Sidorova, A. H. Strel'chuk, and V. E. Chel-

Translated by Dave Parsons