共查询到20条相似文献,搜索用时 31 毫秒
1.
Shimbo M. Furukawa K. Tanzawa K. Higuchi T. 《Electron Devices, IEEE Transactions on》1988,35(1):124-128
Surface-charge configurations, together with stability under bias-temperature (BT) stress, for F-doped and Na-doped lead borosilicate glass were investigated by using C -V and I - V measurements on metal-glass-silicon capacitors and on diodes passivated with the glass. The C -V characteristics showed an increase in negative charge for F doping and in positive charge for Na doping. Alkali impurities in the glass mainly controlled the surface-charge shift during BT, but additional changes, similar to those for Na doping but reversing the sign of the charge, took place by F doping. The leakage current decrease in the diode passivated with F-doped glass, which contradicts the results of C -V measurement, may be due to the education of the generation current by the interaction between the silicon surface and F- ions 相似文献
2.
Energy transfer from selectively formed metastable states of SiO is used to pump sodium-atom laser amplifiers at λ≈569 nm (4d 2D -3p 2P ), λ≈616 nm (5s 2S -3p 2 P ), and λ≈819 nm (3d 2D -3p 2P ). The a 3Σ+ and b 3Π states of SiO are generated in high yield from the Si+N2O→SiO+N2 reaction. The energy stored in the triplet states is transferred in a highly efficient collisional process to pump sodium atoms to their lowest excited 3d 2 D , 4d 2D , and 5s 2S states. Adopting a sequence in which high concentrations of silicon and sodium atoms are mixed and oxidized, a continuous amplification (gain condition) is monitored which suggests the creation of a population inversion among the receptor sodium-atom energy levels and forms the basis for full cavity oscillation on the Na4 d 2D -3p 2P transition at 569 nm 相似文献
3.
The surface recombination velocity s for silicon surfaces passivated with thermal oxide was experimentally determined as a function of surface phosphorus concentration for a variety of oxidation, anneal, and surface conditions. This was accomplished by measuring the emitter saturation current density J 0 of transparent diffusions for which the J 0 is strongly dependent on s . At the lowest doping levels, the value of s was confirmed by measurements of s on substrates with uniform phosphorus doping. The impact of these measurements on solar cell design is discussed 相似文献
4.
Pole-Shang Lin Chia-Haur Chang 《Electron Device Letters, IEEE》1991,12(11):638-640
The authors present a technique to determine the work-function difference from a plot of the threshold voltage (V T) versus oxide thickness (T ox) curve. The extraction errors caused by the electrical characteristics of the oxide and the SiO 2/Si interface can be minimized by the V T-Tox technique. The boron segregation coefficient can be calibrated from the slope of the V T -Tox curve. Comparisons between the experimental data and simulation results are made, and good agreement is obtained 相似文献
5.
The design and fabrication of an InP MESFET with excellent I -V characteristics are reported. A record high transconductance of 110 mS/mm was measured for a 1-μm gate length direct-Schottky-contact InP MESFET, where the InP surface was not passivated or treated prior to the deposition of the gate contact. Microwave measurements show an f max of 11.6 GHz for this typical nominal 1-μm gate length device. A p-type planar doped layer was inserted between the buried n-type channel and the device surface at 18 nm from the gate metal. This planar layer enhances the Schottky barrier height and device performance 相似文献
6.
The emitter saturation current density, J 0 was measured on diffused boron emitters in silicon for the case in which the emitter surface is passivated by a thermal oxide and for the case in which Al/Si is deposited on the emitter surface. The oxide-passivated emitters have a surface recombination velocity, s , which is near its lowest technologically achievable value. In contrast, the emitters with Al/Si on the surface have surface recombination velocities which approach the maximum possible value of s . From the J 0 measurements, the apparent bandgap narrowing as a function of boron doping was found. Using this bandgap narrowing data, the surface recombination velocity at the Si/SiO2 interface was extracted for surface boron concentrations from 3×1017 to 3×1019 cm-3 相似文献
7.
A VLSI computation is said to be m -way multilective when each input bit is available m times in either space or time or both. The repeated availability of input bits can save computational energy. For a uniswitch m-way multilective computation, where a wire can switch at most once, it is shown that the energy savings can be as much as a factor of m . A multiswitch m -way multilective computation can save up to a factor of √ m switching energy. Tighter energy lower bounds are derived for a circuit with the input/output (I/O) pads located on the border. These boundary computations seem to cost an additional factor ranging from √log n to log n in switching energy. The author extends the energy lower bounds for the multilective case, for a chip with aspect ratio a . The additional energy cost ranges from a factor of √a to a factor of a 相似文献
8.
Short codes with a given covering radius 总被引:1,自引:0,他引:1
Brualdi R.A. Pless V.S. Wilson R.M. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1989,35(1):99-109
The covering radius r of a code is the maximum distance from any vector in the space containing the code to the nearest codeword. The authors introduce a new function l (m ,r ), called the length function, which equals the smallest length of a binary code of codimension m and covering radius r . They investigate basic properties of the length function. Projective geometries over larger fields are used to construct families of codes which improve significantly the upper bound for l (m ,2) obtained by amalgamation of Hamming codes. General methods are developed for ruling out the existence of codes of covering radius 2 with a given codimension and length resulting in lower bounds for l (m ,2). A table is presented which gives the best results now known for l (m ,r ) with m ⩽12 and r ⩽12 相似文献
9.
Hou X.-D. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1990,36(4):895-899
Some new lower bounds on |C| for a binary linear [n , k ]R code C with n +1=t (R +1)-r (0⩽r <R +1, t >2 odd) or with n +1=t (R +1)-1(t >2 even) are obtained. These bounds improve the sphere covering bound considerably and give several new values and lower bounds for the function t [n , k ], the smallest covering radius of any [n , k ] code 相似文献
10.
van Wee G.J.M. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1988,34(2):237-245
The sphere bound is a trivial lower bound on K (n ,R ), the minimal cardinality of any binary code of length n and with covering radius R . By simple arguments it is considerably improved, to K (n ,1)⩾2 n/n for n even. A table of lower and upper bounds on K (n ,R ) for n ⩽33, R ⩽10 is included 相似文献
11.
The authors consider the problem of bounding the information capacity of saturation recording. The superposition channel with additive Gaussian noise is used as a model for recording. This model says that for a saturation input signal, x (t ) (i.e., one that can assume only one of two levels), the output can be expressed as y (t )=x ˜(t )+z (t ) where x ˜(t ) is a filtered version of the input x (t ) and z (t ) is additive Gaussian noise. The channel is described by the impulse response of the channel filter, h (t ), and by the autocorrelation function of the noise. A specific example of such a channel is the differentiated Lorentz channel. Certain autocorrelation and spectrum expressions for a general Lorentz channel are derived. Upper and lower bounds on the capacity of saturation recording channels are described. The bounds are explicitly computed for the differentiated Lorentz channel model. Finally, it is indicated how the derived bounds can be applied in practice using physical measurements from a recording channel 相似文献
12.
Kieffer J.C. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1991,37(2):263-268
The rate and distortion performance of a sequence of codes along a sample sequence of symbols generated by a stationary ergodic information source are studied. Two results are obtained: (1) the source sample sequence is encoded by an arbitrary sequence of block codes which operate at a fixed rate level R, and a sample converse is obtained which states that, with probability one, the lower limit of the code sample distortions is lower bounded by D (R ), the value of the distortion rate function at R ; (2) the source sample sequence is encoded by an arbitrary sequence of variable-rate codes which operate at a fixed distortion level D , and a sample converse is obtained which states that, with probability one, the lower limit of the code sample rates is lower bounded by R (D ), the value of the rate distortion function at D . A novel ergodic theorem is used to obtain both sample converses 相似文献
13.
Wende Chen Honkala I.S. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1990,36(3):664-671
The authors prove combinatorial lower bounds for K q (n ,R ), the minimal cardinality of any q -ary code of length n and covering radius R . Tables of lower bounds for K q(n ,R ) are presented for q =3, 4, 5 相似文献
14.
The problem of counting the number of cuts with the minimum cardinality in an undirected multigraph arises in various applications, such as testing the super-λ-ness of a graph, as described by F.T. Boesch (1986), and calculating upper and lower bounds on the probabilistic connectedness of a stochastic graph G in which edges are subject to failure. It is shown that the number |C ( G )| of cuts with the minimum cardinality λ(G ) in a multiple graph G =(V ,E ) can be computed in O (|E |+λ(G )|V |2 +λ(G )|C (G )||V |) time 相似文献
15.
Shamai S. Ozarow L.H. Wyner A.D. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1991,37(6):1527-1539
Bounds are presented on I i.i.d.-the achievable information rate for a discrete Gaussian Channel with intersymbol interference (ISI) present and i.i.d. channel input symbols governed by an arbitrary predetermined distribution p x(x ). The lower and upper bounds on I i.i.d. and I are formulated. The bounds on I i.i.d. are calculated for independent equiprobably binary channel symbols and for causal channels with ISI memory of degree one and two. The bounds on I i.i.d. are compared to the approximated (by Monte Carlo methods) known value of I i.i.d. and their tightness is considered. An application of the new lower bound on I i.i.d. yields an improvement on previously reported lower bounds for the capacity of the continuous-time strictly bandlimited (or bandpass) Gaussian channel with either peak or simultaneously peak power and bandlimiting constraints imposed on the channel's input waveform 相似文献
16.
The authors describe a novel technique for direction-of-arrival estimation based on computing a permutation matrix E and a QR factorization RE =HB of the permuted covariance matrix R , such that a possible rank deficiency of R is revealed in the triangular factor B having a minimum norm lower right block. A subset of the columns of the orthogonal matrix, H , is shown to be orthogonal to the direction vectors of sources and hence can be used to estimate their bearings. The cost of this algorithm is only slightly more than that of one QR factorization, but is much lower than that of an eigen-decomposition. Simulation results are included to show that the proposed method performs nearly as well as MUSIC in terms of signal resolution, bias, and variance of the estimated bearings 相似文献
17.
Kizilyalli I.C. Artaki M. Shah N.J. Chandra A. 《Electron Devices, IEEE Transactions on》1993,40(2):234-249
Scaling properties of n+-AlxGa1-xAs/GaAs MODFETs with submicrometer gate lengths (L G=0.50 to 0.05 μm) are examined, using Monte Carlo methods. High-frequency performance of MODFETs can be improved by scaling the gate lengths, but various studies suggest that there exists a lower limit for the gate after which no improvement should be expected. The lower limit is determined here to be ≈0.10 μm. Devices with smaller gate lengths than 0.1 μm exhibit degraded transconductance (g m), large shift in threshold voltage due to poor charge control in the channel, and a sharp reduction in output resistance (R o). It is shown that the drain current saturation in MODFETs is not caused by the velocity saturation effect, but by channel pitch-off. Electron velocities calculated from Monte Carlo simulations and extracted from g m and f t measurements are reconciled 相似文献
18.
van Zanten A.J. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1991,37(4):1229-1233
A number system is developed for the conversion of natural numbers to the codewords of the Gray code G (n ,k ) of length n and weight k , and vice versa. The focus is on the subcode G (n ,k ) of G (n ) consisting of those words of G (n ) with precisely k 1-bits, 0<k <n . This code is called the constant weight Gray code of length n and weight k . As an application sharp lower and upper bounds are derived for the value of |i -j |, where i and j are indices of codewords g i and g j of G (n ,k ) such that they differ in precisely 2 m bits 相似文献
19.
Hydrogen annealing at 700-1100°C for 0-300 s has been combined with SiO2 formation by rapid thermal processing (RTP). The SiO2 films formed with the above processes were evaluated by C -V and I -V measurements and by time-dependent dielectric breakdown (TDDB) tests. These films provide longer time to breakdown andless positive charge generation than SiO2 films formed without H 2 annealing. In particular, the SiO2 formation-H2 annealing SiO 2 formation process is quite effective in improving the dielectric strength of the thin RTP-SiO2 film 相似文献
20.
Honkala I.S. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1988,34(2):326-329
G.D. Chen et al. (ibid., vol.IT-32, p.680-94, 1986) presented two new lower bounds for K (n ,R ), where K (n ,R ) denotes the minimum cardinality of a binary code of length n and covering radius R . The author shows that a slight modification gives further improvements and some examples are given to confirm the argument. Codes that have a certain partitioning property are considered 相似文献