摘要:

Investigations have revealed contrast variations in twisted nematic liquid-crystal matrix displays. These are consistent with effective changes in the applied torque due to relaxation of the permittivity at the frequencies at which significant power is applied in the Fourier spectrum of the stimulus waveform.

DOI:10.1049/ip-i-1.1986.0027

出版商:IEE    

年代:1986

数据来源: IET

摘要:

We compare the performance of amorphous silicon/silicon nitride field-effect transistors having either nitride or silicon deposited first. In the case of silicon being the first layer, underlying source and drain contacts of aluminium or chromium were compared (as aluminium may react or diffuse more easily than chromium). The best devices required the nitride to be deposited first, following which it was essential to remove impurities such as ammonia from a single chamber system by dilution purging, before depositing silicon. Contributory influences on the poor characteristics of the alternative structure include the higher temperature necessary for nitride deposition, even when this overlies the silicon, and the bombardment of the silicon surface with energetic species from the nitride source gases.

DOI:10.1049/ip-i-1.1986.0029

出版商:IEE    

年代:1986

数据来源: IET

摘要:

A mathematical formula is presented for the current-voltage characteristic of the VMOS power transistor. The two parameters of this model can be easily extracted from different regions in the device characteristics. By using this formula, the implementation of a new VMOS power transistor model into the source code of circuit-simulation programs, such as SPICE, is feasible.

DOI:10.1049/ip-i-1.1986.0030

出版商:IEE    

年代:1986

数据来源: IET

摘要:

Numerical computation of induced current density, power gain, conversion efficiency, harmonic generation etc., pertaining to an O-type travelling wave amplifier based on the theory of Part 1 is presented and comparison with the results of other theories and experiments is made.

DOI:10.1049/ip-i-1.1986.0031

出版商:IEE    

年代:1986

数据来源: IET

摘要:

An arbitrary semiconductor junction is used to obtain an equation for junction current density in terms of the conditions at the boundaries between the space charge and the quasineutral bulk regions on each side of the junction. Included are the effects of recombination in the space charge volume as well as bandgap narrowing and ambipolar diffusion effects in the bulk regions at these boundaries. The equation also accounts for the effects of drift field, which is neglected in other theories, and demonstrates that it exerts a form of cross-coupled modulation upon current flow. Under certain conditions, it may be shown that the current density is largely determined by the carrier density gradient at the space charge to bulk boundaries. A solution for carrier density gradient, which is obtained by one integration of the diffusion equation, does not require a precise solution for carrier density profile and may be used to model bulk region Auger recombination with the aid of the derived equation for current density. This contribution may find use in the design of snubber diodes.

DOI:10.1049/ip-i-1.1986.0033

出版商:IEE    

年代:1986

数据来源: IET