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Fermi energy and band-tail parameters in heavily doped semiconductors
World Abstracts on Microelectronics and Reliability of Sight free space propagation and the mm wave circular waveguide systems will be rather less than for existing microwave links. The circular waveguide systems will have repeaters every 15 km or so each with 20-40 separate channels. Installation of these systems on major intercity trunk routes is scheduled to commence in the latter half of the present decade. This market is large enough to justify the development of monolithic circuits both for base bands up to 2 GHz and for the IFs which will require to be centred at 3-0-3.5 GHz to accommodate them. There is, therefore, a strong market incentive for the development of digital circuits for operation up to 2 GHz and analogue circuits up to about twice this frequency. Recent technology improvements in the area of MESFET-Schottky circuits and circuits based on Gunn devices are discussed in particular relation to their potential capability to meet the needs of this market. Since it is the function of this brief paper to review the state of the art it is not proposed to include discussion of the more sophisticated end of the silicon technology despite the fact that such circuits may well be used for communications systems requiring base band and IF circuits with specifications which are one stage down in difficulty on the circular waveguide requirements (e.g., 120 or 240M Bit base band on 500 MHz IF). Finally, the rather more tenuous possibility of GaAs monolithic circuits for RF operation right up to the top of the mm wave band ( - 1 0 0 GHz) is assessed.
IC converts voltage to frequency. BERNARD COLE. Electronics August 21, 1975. p. 112. Commercial version of monolithic circuit offers linearity to ±1% and bandwidth of 10l) kilohertz, sells for $3 each in 100-lots.
A new generation of displacement transducers. J. E. L. HOLLIS. Electronic Engineering March 1975. p. 52. Integrated circuit technology has been used to design a range of extremely small, lightweight, displacement transducers. 7. S E M I C O N D U C T O R
INTEGRATED
Fermi energy and band-tail parameters in heavily doped semiconductors. H. VAN CONG. J. Phys. Chem. Solids 36, 1237 (1975). The density of states in heavily doped semiconductors is investigated by using the Green function method and the Feynman-path integral formulation applied to n-type semiconductor. It is suggested that in the present theory it takes an approximate form exp {v/(3/2)(E/~r)} for negative energies, and a parabolic form for positive energies. The Fermi energy and the band-tail parameters at low temperatures are calculated in the Thomas-Fermi approximation. An application to n-type GaAs is given; the present results are also compared to the theoretical results of Hwang and Brews at 77°K.
Boron and phosphorous diffusion through an SiO2 layer from a doped polycrystalline Si source under various drive-in ambients. K. SHIMAKURA,T. SuzuKi and Y. YADOIWA. Solid State Electronics 18, 991 (1975). The diffusion of boron and phosphorus into thermally grown SiO2 from a doped polycrystalline Si source has been found to be dependent on drive-in ambients and to be especially fast in an H2 ambient. Diffusion coefficients have been calculated by the two boundary diffusion model. It was found that the diffusion coefficient of boron in SiO2 is about two orders of magnitude larger than that of phosphorus. This fact is very important for Si gate processes. For P-channel Si gate transistors, boron diffused in the gate SiO2 film from the doped polycrystalline Si gate electrode causes new types of instabilities in transistor characteristics.
23
Experimental results demonstrate the capabilities of the device as a displacement transducer and consideration of the basis of the design allows its potentialities to be examined.
lCs interface keyboard to microprocessor. DONALD P, MARTIN and KERRY S. BERLAND. Electronics March 6 1975. p. 83. A compact, economical interface between a keyboard and a microprocessor can be designed with only three integrated-circuit chips. The ICs are a 5740 MOS scanning keyboard encode, a 2812 MOS first-in/first-out (FIFO) memory, and a 74125 quad three-state buffer. All three can be mounted with the standard array of keyswitches and diodes on a single circuit board. 1-kilobit C-MOS RAM offers low price, power. CHARLES COHEN. Electronics February 20 1975. p. 19E, Only l0 nanowatts per bit required for standby supply; ionimplantation technique allows chip to be small.
Bipolar LSh 10,000 gates in sight. LAURENCE ALTMAN. Electronics March 6 1975. p. 57. A one-chip 16-bit programable LSI processor operating at the speeds fast enough for today's medium- and large-scale computers? The prospect appeared preposterous a few years ago. But although the ability to put 10,000 gates on one bipolar chip is still some two or three years away, the singleelement gate of new forms of logic already makes this kind of performance a hard reality. For example, Schottky integration injection logic has gate propagation delays of 1-5 nsec, gate power dissipation in the nanowatt range, and gate sizes of 4-5 square mils. lC compresses, expands analog signals. BERNARD COLE. Electronics June 26 1975. p. 117. Bipolar linear chip replaces discrete components as communications compandor; includes reference voltage, converters, high-gain op amp. CIRCUITS,
DEVICES
AND
MATERIALS
Ultrasonic mean free path in a granular aluminium film. M. TACHIKI, H. SALVO, JR., D. A. ROBINSON and M. LEVY. Solid State Communications 17, 653 (1975). The ultrasonic mean free path has been measured and compared to the electrical mean free path of a thin granular aluminum film. They have been found to differ by an order of magnitude which is believed to indicate that mean free path determined ultrasonically is for the A1 metal while the one determined electrically is for the AI-Al203 matrix structure.
Injection current flow through thin insulator films. THOMAS J. O'REILLY and JAMES DELucIA. Solid State Electronics 18, 965 (1975). The equations and boundary conditions describing injection current flow through insulators are investigated for the case of thin insulator films. The carrier mobility is assumed to be constant and trapping is neglected. The thickness of the insulator film is taken to be small enough so that surface properties are significant. It is found that electrons flowing in from the metal contacts can increase the insulator conductivity by orders of magnitude. The diffusion term in the current equation is not neglected, and it is found that this enhances the quadratic Mott-Gurney current term. The theoretical results are compared with previous experimental results.
Characteristic electron energy losses in germanium. L C SPELLER and H. MENDLOWITZ. d. Phys. Chem. Solids 1975. Vol. 36. p. 1229. The characteristic electron energy
IC converts voltage to frequency. BERNARD COLE. Electronics August 21, 1975. p. 112. Commercial version of monolithic circuit offers linearity to ±1% and bandwidth of 10l) kilohertz, sells for $3 each in 100-lots.
A new generation of displacement transducers. J. E. L. HOLLIS. Electronic Engineering March 1975. p. 52. Integrated circuit technology has been used to design a range of extremely small, lightweight, displacement transducers. 7. S E M I C O N D U C T O R
INTEGRATED
Fermi energy and band-tail parameters in heavily doped semiconductors. H. VAN CONG. J. Phys. Chem. Solids 36, 1237 (1975). The density of states in heavily doped semiconductors is investigated by using the Green function method and the Feynman-path integral formulation applied to n-type semiconductor. It is suggested that in the present theory it takes an approximate form exp {v/(3/2)(E/~r)} for negative energies, and a parabolic form for positive energies. The Fermi energy and the band-tail parameters at low temperatures are calculated in the Thomas-Fermi approximation. An application to n-type GaAs is given; the present results are also compared to the theoretical results of Hwang and Brews at 77°K.
Boron and phosphorous diffusion through an SiO2 layer from a doped polycrystalline Si source under various drive-in ambients. K. SHIMAKURA,T. SuzuKi and Y. YADOIWA. Solid State Electronics 18, 991 (1975). The diffusion of boron and phosphorus into thermally grown SiO2 from a doped polycrystalline Si source has been found to be dependent on drive-in ambients and to be especially fast in an H2 ambient. Diffusion coefficients have been calculated by the two boundary diffusion model. It was found that the diffusion coefficient of boron in SiO2 is about two orders of magnitude larger than that of phosphorus. This fact is very important for Si gate processes. For P-channel Si gate transistors, boron diffused in the gate SiO2 film from the doped polycrystalline Si gate electrode causes new types of instabilities in transistor characteristics.
23
Experimental results demonstrate the capabilities of the device as a displacement transducer and consideration of the basis of the design allows its potentialities to be examined.
lCs interface keyboard to microprocessor. DONALD P, MARTIN and KERRY S. BERLAND. Electronics March 6 1975. p. 83. A compact, economical interface between a keyboard and a microprocessor can be designed with only three integrated-circuit chips. The ICs are a 5740 MOS scanning keyboard encode, a 2812 MOS first-in/first-out (FIFO) memory, and a 74125 quad three-state buffer. All three can be mounted with the standard array of keyswitches and diodes on a single circuit board. 1-kilobit C-MOS RAM offers low price, power. CHARLES COHEN. Electronics February 20 1975. p. 19E, Only l0 nanowatts per bit required for standby supply; ionimplantation technique allows chip to be small.
Bipolar LSh 10,000 gates in sight. LAURENCE ALTMAN. Electronics March 6 1975. p. 57. A one-chip 16-bit programable LSI processor operating at the speeds fast enough for today's medium- and large-scale computers? The prospect appeared preposterous a few years ago. But although the ability to put 10,000 gates on one bipolar chip is still some two or three years away, the singleelement gate of new forms of logic already makes this kind of performance a hard reality. For example, Schottky integration injection logic has gate propagation delays of 1-5 nsec, gate power dissipation in the nanowatt range, and gate sizes of 4-5 square mils. lC compresses, expands analog signals. BERNARD COLE. Electronics June 26 1975. p. 117. Bipolar linear chip replaces discrete components as communications compandor; includes reference voltage, converters, high-gain op amp. CIRCUITS,
DEVICES
AND
MATERIALS
Ultrasonic mean free path in a granular aluminium film. M. TACHIKI, H. SALVO, JR., D. A. ROBINSON and M. LEVY. Solid State Communications 17, 653 (1975). The ultrasonic mean free path has been measured and compared to the electrical mean free path of a thin granular aluminum film. They have been found to differ by an order of magnitude which is believed to indicate that mean free path determined ultrasonically is for the A1 metal while the one determined electrically is for the AI-Al203 matrix structure.
Injection current flow through thin insulator films. THOMAS J. O'REILLY and JAMES DELucIA. Solid State Electronics 18, 965 (1975). The equations and boundary conditions describing injection current flow through insulators are investigated for the case of thin insulator films. The carrier mobility is assumed to be constant and trapping is neglected. The thickness of the insulator film is taken to be small enough so that surface properties are significant. It is found that electrons flowing in from the metal contacts can increase the insulator conductivity by orders of magnitude. The diffusion term in the current equation is not neglected, and it is found that this enhances the quadratic Mott-Gurney current term. The theoretical results are compared with previous experimental results.
Characteristic electron energy losses in germanium. L C SPELLER and H. MENDLOWITZ. d. Phys. Chem. Solids 1975. Vol. 36. p. 1229. The characteristic electron energy