摘要:

The method of contact ionization is used to produce a three‐component plasma (Cs+, Cl−, e−) in theQ‐device BARBARA using a beam of Cesium chloride. The end‐plate temperature controls the concentration of Cl−, which can be varied in a wide range. The density of negative ions is obtained from the difference between the positive ion density given by a Langmuir probe and the electron density given by a microwave resonator. A high concentration of negative ions is achieved.

ISSN:0021-8979    

DOI:10.1063/1.1659439

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Isothermal changes in the electrical resistivity of lithium‐diffused silicon have been measured in the range of 370°–650°C. Silicon with high and low oxygen content was used to study the effect of lithium‐oxygen interaction. The change of the isothermal curve due to the radiation was also studied. Some important observations can be made: (1) There is evidence of the formation of a new defect at high temperature which would explain the observed redegradation in the post radiation recovery in silicon with low oxygen concentration. (2) There is a very slow formation of a donor state in silicon with high oxygen concentration. (3) The final resistivity after a long period of heat treatment is dependent on the initial donor concentration before the diffusion of lithium in the silicon with low oxygen concentration, while in the case of high oxygen concentration the final resistivity is substantially independent of the initial donor concentration.

ISSN:0021-8979    

DOI:10.1063/1.1659440

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Some unusual annealing properties of the radiation damage in lithium‐diffused silicon are discussed. These properties are (1) spontaneous room‐temperature recovery, (2) the effect of oxygen content in silicon on the recovery, (3) the effect of the defect concentration on the recovery, (4) high damage effect on the recovery, and (5) redegradation. A kinetic equation is formulated by introducing the time dependence of free lithium concentration in the system to the kinetic equation of the repairing of the damage. The results successfully describe all the properties listed above.

ISSN:0021-8979    

DOI:10.1063/1.1659441

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The diffusion of zinc into silicon was investigated by a sealed‐quartz‐tube, two temperature method. The following diffusion variables were considered: time (15 min‐16 h), silicon type (NandP), temperatures (900°–1100°C), zinc temperatures (600°–900°C), and the effect of chemical treatments. A value of 4.4×10−8cm2/sec was computed for substitutional zinc diffusivity in silicon, with silicon wafers at 1000°C and zinc source at 700°C. While the diffusion of zinc followed the usual square root dependence on time, there was an initial time lag of several minutes very probably due to the ever present thin SiO2films on the surface of silicon. When these SiO2surface layers were made intentionally thicker zinc diffusion virtually stopped. In the pressure range between 50 and 760 Torr, the penetration of zinc was found to be a nonlinear function of the vapor pressure of zinc. The effects of heat treatments at 1000°C on electrical resistance of silicon with and without zinc were also studied and compared. Finally, zinc was diffused into N+‐Ppower diode structures.

ISSN:0021-8979    

DOI:10.1063/1.1659442

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

We have computed the excess carrier lifetime for conduction band‐heavy‐hole band Auger recombination forn‐type Hg1−xCdxTe. The general theory assuming parabolic bands and a constant value for the overlap integrals has been developed by Beattie and Landsberg. We have included the effects of nonparabolic bands and have used thef‐sum rule to obtain thekdependence of the overlap integrals. Using numerical techniques we have evaluated the temperature dependence of the lifetime for severalxvalues.

ISSN:0021-8979    

DOI:10.1063/1.1659443

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Current‐voltage characteristics from 140° to 350°K are measured on a longp+‐&pgr;‐n+silicon structure biased into the double‐injection regime. The I‐V characteristics obey aJ∝V2/L3relation throughout the considered temperature range, and the magnitude of the double‐injection current is predicted within 10% by the Lampert expressionJ= (9/8)q&mgr;p&mgr;n&tgr; (p0‐n0)V2/L3. The transient response of double injection as analyzed by Baron provides a direct measure of the common high‐level lifetime &tgr;, which is given by the formula &tgr;=30.7×10−6(T/298)1.93±0.23sec. Conductivity, Hall effect, and the large‐signal‐step‐response method of Dean establish the electron and hole mobility as &mgr;n=1280 (298/T)1.75±0.31cm2/V‐sec and &mgr;p=410 (298/T)2.18±0.04cm2/V‐sec, respectively, for 140°≤T≤350°K. The consistency between the measured values of the lifetime and mobilities with values reported by the literature establishes that the temperature dependence of a long double‐injectionp+‐&pgr;‐n+silicon device is in agreement with the Lampert expression and the temperature variation of &tgr; (T), &mgr;p(T), and &mgr;n(T). A 14‐MeV neutron irradiation of 1.25×1011n/cm2does not alter the quadratic lawJ∝V2/L3of the device but results in lower current levels when compared to the preirradiation condition. Pulse and dc measurements analogous to the preirradiated case give&tgr;ˆ=8.9×10−6(T/298)0.68±0.07 sec,&mgr;ˆp=385(298/T)1.30±0.10 cm2/V−sec, and&mgr;ˆn=1160(298/T)1.28±0.21 cm2/V−secfor the carrier lifetime and mobilities, respectively. After irradiation reasonable agreement is found between the measured double‐injection current and that predicted from Baron's first‐order correction of the Lampert expression for diffusion and thermal generation effects.

ISSN:0021-8979    

DOI:10.1063/1.1659444

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Type II donor‐acceptor pair spectra involving the shallow group IIA acceptor Mg and the group VI donors S and Te have been observed from GaP crystals grown from Ga solution in an open‐tube furnace system. Magnesium can be an optically active inadvertent contaminant in high‐purity GaP. Crystals containing ∼1017cm−3of these desired impurities, added intentionally, exhibited sharp structure due to electron‐hole recombinations at discrete donor‐acceptor pairs, with negligible contamination from unwanted spectra. The transition energies in these spectra can be closely fitted for shell numbersm≳20(pair separation≳17 Å) by an expression which includes only the coulomb monopole term for the final state interaction and a van der Waals term for the initial state interaction, using low‐temperature static dielectric constant. This analysis yields the activation energy of the Mg acceptor in GaP, (EA)Mg=53.5±1 meV, substantially different from previous estimates derived from electrical transport and impurity Raman scattering measurements. Trends in the activation energies of the three Ga‐site acceptors and three P‐site acceptors known in GaP are discussed qualitatively.

ISSN:0021-8979    

DOI:10.1063/1.1659445

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The variation of current with magnetic field for constant applied electric field has been measured in thin films of InSb in which the transverse magnetic field is aligned both normal to and in the plane of the sample. These measurements have been performed for values of electric field both below and above that required for impact ionization of the lattice. The results are shown to be well explained by the magnetoresistance theories, of Wieder and Pikus, which indicate a maximum contribution of the surfaces to the measured magnetoresistance for a sample whose thickness is ∼1.4 times the bulk diffusion length. From the results it is estimated that the ratio of the recombination rates associated with the two surfaces of the films is ∼0.4, the larger recombination rate being associated with the free surface.

ISSN:0021-8979    

DOI:10.1063/1.1659446

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The contribution to the electrical conductivity of grain boundaries in polycrystalline Cu2O was measured in vacuum and in air between 200° and −145°C. It was found to follow a simple exponential temperature dependence with a single activation energy of about 0.31 eV. Heat treatment at 200°C can be used to vary the contribution of the grain boundaries from 5×10−9&OHgr;−1in air to 8×10−10&OHgr;−1in vacuum at room temperature. The effects are explained by impurities conglomerating at the grain boundaries and the diffusion of oxygen along these boundaries. The deterioration of the volt‐ampere characteristics of cuprous oxide rectifiers after preparation or as a result of extensive heating above 150°C is explained by the same mechanism. The studies of the rectifiers were based on measurements on capacity and resistance of the barrier layers at room temperature.

ISSN:0021-8979    

DOI:10.1063/1.1659447

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Using computer solutions of the relevant differential equations, many authors have determined the velocity for which traveling domains exist in a semiconductor with a region of negative differential mobility. Recently, Gunn presented a topological argument leading to a closed form equation for the velocity of a finite amplitude domain. For the case of a domain shape controlled by diffusion we show that Gunn's argument is based on a necessary, but not sufficient, condition that a certain singular point be a center. This leads to an incorrect expression for the domain velocity for all but infinitesimal amplitude domains. The topological character of each solution as the velocity parameter is varied is also described.

ISSN:0021-8979    

DOI:10.1063/1.1659448

出版商:AIP    

年代:1970

数据来源: AIP