SU1324525A1 - Method of treating semiconducting material - Google Patents

Description

(46) 05/30/92. Bul And 20

(21) 3922652/25

(22) 07/01/85

(71) Scientific Research Institute of Nuclear Physics at the Tomsk Polytechnic Institute; S.M.Kirov

(72) A.D.Pogrebn, S.A. Vorobev, Yu.Yu. Kryuchkov, A.A. Verigin and. Koshcheev (53) 621.382.002 (088.8)

(56) Patent of Great Britain f 1365570, cl. H 01 L 21/263, 1970.

Patent of Germany 9 20357033, cl. N. 01 L 21/263, 1970.

(54) METHOD FOR TREATING HEELOW-MADE MATERIALS

(57) The invention relates to micro-, electronics, and specifically to methods for changing the properties of semiconductor materials and devices by irradiating charged particles. The purpose of the image. Neither is an increase in the radial strength of semiconductor materials, which is achieved by irradiating materials with a pulse of nanosecond particles at an energy density of 1 J / cm. This improves the structure of the surface layer, and in depth creates a defect layer that serves as a drain for defects arising from irradiation. As a result, the radiation resistance increases by 3-8 times. 5 il. The invention relates to the technology for the manufacture of semiconductor materials, in particular, to methods for processing semiconductor crystals and devices. - increase radiation resistance and increase the speed of the method. Fig. 1 shows the differential profile of defects (N) of an interstitial type, reconstructed from, the energy spectra of the reverse-reflection. sulfur ions from GaAs crystals exposed to a high-current electron beam with a pulse energy density of 0.8 J / cm, pulse and pulse duration of 90 ns; figure 2 shows the defect profiles of vacancy jioro type (NO) in the depth of irradiated GaAs crystals; FIG. 3 shows the dependence of the width Γ at half-height of the curves of the dependence of the count rate of zitrons on the isochronous annealing temperature T for GaAs crystals; in fig. profiles of defects of vacancy type (NO) at the depth of irradiated Si crystals are given; NV Fig. 3 shows the dependence of the lifetime t of minor, charge carriers on the irradiation dose w. 2, curve 1 is for GaAs irradiated by protons on a cyclotron with an energy of MeV, a dose of -2-10 cm; curve 2 — for GaAs irradiated with a high-current ion beam (SIP) of hydrogen with an energy of 0.5 to A, 8 MeV and an energy density per pulse of 0.7 J / cm imp; curve 3 — for GaAs, hydrogen irradiated with SIP with energy from 0.5 to 4.8 MeV with a duration of 1000 NS and then irradiated with protons on a cyclotron with MeV, dose F 2 10 cm-g. Fig. 3 shows curve 4 for -GaAs irradiated by protons on a cyclotron with an energy of 10 MeV, doses of 2 and 10. cm (annealing time of each point 15 min); curve 5 for GaAs, irradiated carbon with SIP with energy of 19.5 MeV, energy density 1, OJ / cm pulse duration of 5.10 s and then irradiated with a stationary beam of protons with energy of 10 MeV, dose F and 2-10 cm2. FIG. 4 shows curve 6 for p-type Si, depleted F-particles, on a cyclotron with IzV energy, a dose of "5.910 cm-; curve 7 for Si irradiated with a high-current carbon beam with an energy of 2.5 to 10 MeV and an energy density of 0.8 J / cm — imp and then A-particles with MeV and a dose of 6.8-10 curve .8 for Si irradiated with HIPS carbon with E - 25-10 MeV and an energy density of 1.1 J / cm imp and then also irradiated with oi-particles with MeV and a dose of cm; curve 9 for Si, 2 -10-g carbon produced by CIP, 5-10 MeV and an energy density of 1.4 J / cm. imp On FIG. 3 Fivedeny curve 10 for Si, Irradiated by electrons with an energy of 5.6 MeV on the Microtron; curve 11 for Si irradiated with a high-current electron beam (BOT) with an energy density of 0.9 J / cm-imp and then again irradiated with electrons at the Microtron; curve 12 for Si irradiated by BOT with an energy density of 1.2 J / cm-imp and then electrons on a mihrotron. The proposed method is carried out as follows. The original semiconductor material, for example, Si and GaAs single crystals, irradiates an SIP with an energy density of 0.7–1.2 J / cm –imp. For crystals, si and O, 6–1.0 J / cn-imp for semiconductor materials based on GaAs. In this case, an annealing zone of defects is formed in the crystal (due to the recrystallization of the layer over the depth of the ion beam), beyond the annealing area there is a transition zone with a high density of defects, which upon further irradiation of semiconductor materials is the flow region of the formed defects (or, in other words, stopping radiation defects) It was experimentally obtained that, when a high-current ion beam is irradiated, Si-based semiconductor materials with an energy density per pulse are less than 0.7 J /cm. imp, i.e. 0.6; 0.5, etc. J / cm.imp., no increase in radiation resistance was found, with partial absorption of energy above 1.2 J / c. An imp occurs the formation of a significant concentration of structural defects (ie, more than in the starting material) and the semiconductor material degrades. Similar results were obtained for semiconductor materials based on GaAs: when these materials were irradiated with a high-current ion beam with an energy density per pulse less than 0.6 J / cm. Imp was also not detected radiation resistance, at energy densities above 1.0 J / cm imp, a high concentration of structure defects is formed, much Bbmie than in the source material, and the semiconductor material degrades PRI me R. Monocrystals of n-type GaAs lasers doped with tellurium to a concentration of N 2.8 10 and p-type single crystals of Si doped to a concentration of N 7.3 MO cm- are used. Irradiation with a stationary proton beam (to induce radiation defects and check radiation resistance) is carried out on a cyclotron with an energy of MeV, current density j 0.2-0.5 μA / cm with various doses. Accelerator Annealing with beam parameters is used as high-current accelerators. electrons: KeV energy, E maize 40-KeV, current density j (10-1,5) «« 10 L / cm, pulse duration. 30-100 NS, T, 1.5-100 NS and J IV / V / nv.fLn accelerator with high-current beams of Tonus and Vera ions with parameters of hydrogen, carbon and nitrogen ions; energy E "-0.2-0.4 MeV ;. J-25-350 A / cm, t, "50-80 not; 102-10 NS. To study the formation of defects, methods of annihilation of positrons, backscattering of channeling ions, measurement of the lifetime of minority charge carriers, which allow to obtain a complete picture of the processes that occur in semiconductors after exposure to high-current beams of charged particles, are used. From dannk figure 1 it follows that the irradiation of a pulsed electron beam leads to the creation of defects (in the depth of the annealing zone). It is possible to do more: pour three areas: a surface peak with a thickness of 100–200 A, grafted as a result of poor surface treatment of crystals; the defect-free area (or zone of annealing of defects), lying behind the surface peak to a depth of 5300 A, and the silion-disturbed area with a significant concentration of defects (| 10 cm-). The area where there are no defects (annealing zone) appears as a result of radiation annealing. In the area (re-entry zone) where defects form, at a given energy density, it occurs. As can be seen from the Gigout of their results not shown in Fig. 2, when the CIP is irradiated with hydrogen, the GaAs crystals in them form a transition zone with a high concentration of defects induced by the CIP. It may be noted that after irradiation of HIP with hydrogen with an energy density of 0.7 J / cm imp and then subsequent irradiation with protons on the cyclotron (to check radiation resistance) of GaAs crystals (curve 3), the concentration of defects formed in the annealing zone is much lower (with : 3.5 times) than in the case of irradiating GaAs with only protons on the cyclotron (curve 1). The presented results show the increase in the radiation resistance of GaAs-based semiconductor materials. In order to obtain a more differentiated picture of the defects that occurred after irradiation with high-current beams of charged particles and subsequent irradiation, isochronous annealing of materials based on GaAs was carried out. From the obtained results (Fig. 3) it can be seen that the irradiation of the initial GaAs crystal with a stationary proton beam (curve 4) leads to the formation of three types of defects (three stages of annealing) with a total concentration of f, NV 3 10 def. After CIP carbon is irradiated and then a stationary proton beam of GaAs crystals (curve 5) followed by isochronous annealing, only two stages of annealing are formed with a lower concentration of defects (N U 6.8-10 def.), I.e. only vacancy clusters and possible dislocations are formed, the radiation resistance of semiconductor crystals has increased 8.5 times. It is well seen from the presented results that irrespective of the type of particles (electrons, ions), when irradiating half of GaAs-based conductor materials with high-current beams With an energy density of 0.6-1.0 Lj / cm imp and a pulse duration t 10 10 HC increases with radiation and durability is 3-8 times in comparison with the initial crystals or materials. (based on GaAs). Studies on the GaAs (Si, Sn) structures — LEDs with a D. of 0.960, 98 μm showed that after irradiation with a high-current electron beam with an energy density of 0.6-1.0 J / cm-i and a pulse duration of 100-1000, no radiation resistance increased 8 3.5-5 times in comparison with control (source) LEDs. As shown in FIG. The data shows that when irradiating Si p-type CIP carbon with an energy density of 0.8-1.1 J / cm. imp and flyaway particle mi- (for checking radiation resistance) the concentration of defects in the annealing zone is on average 5–8 times less than in the case of irradiation with (particles of the original Si crystal. The obtained result shows an increase in the radiation resistance of semiconductor materials on the basis of Si; From the data of FIG. 5 it is clearly seen that when semiconductor materials from Si are irradiated with a high-current electron beam with an energy density of 0.91.2 J / cm are pulses and then with electrons on a Microtron (to check radiation resistance) the stability of these materials is improved, as evidenced by a decrease in the lifetime of minority charge carriers compared to the control ones. Thus, compared to the prototypes in the proposed processing method, the radiation resistance of semiconductor materials increases by no less than 3.5 times while simultaneously increasing the rapidity no less than 10 times. Forms of the invention The method of processing semiconductor materials, including the irradiation of charged particles, is about m and h. y and with the fact that, in order to increase the radiation resistance and increase the efficiency of the method, semiconductor materials based on silicon and gallium arsenide are irradiated with a pulsed high-current beam of charged 10 "particles to a duration of 10 from its energy density, respectively, from 0.6 to 1, 2 J / cm.

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Claims (1)

Claim 15 Method of processing · semiconductor materials, including irradiation with charged particles, about aphids βίο, ıs and ıs with the fact that, in order to increase radiation resistance and increase the expressivity of the method, semiconductor materials based on silicon and gallium arsenide are irradiated with a pulsed high-current beam charged particles lasting from 104 · to 25 10 s with energy density respectively from 0.6 to 1.2 J / cm *. 1324525