Browse Prior Art Database

Semiconductor Device

IP.com Disclosure Number: IPCOM000049993D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Fang, FF: AUTHOR [+3]

Abstract

An electron temperature gradient in a semiconductor can be employed for microwave generation and switching.

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Semiconductor Device

An electron temperature gradient in a semiconductor can be employed for microwave generation and switching.

This article describes a structure wherein an electron temperature gradient results in diffusion of hot electrons from high resistivity regions to low resistivity regions which in turn produces a runaway situation of increasing resistance so that under appropriate field distribution and temperature gradient a useful negative conductance regime will be present. Such a structure is shown in Fig.
1.

The structure of Fig. 1 is a semiconductor film of moderate doping on a semi-insulating substrate. The film is structured to form thick (d(1)) and thin (d(2)) regions with longitudinal length l(1) and l(2), respectively. Since the conductance in the l(1) d(1) region is larger than that in the l(2) d(2) region, the electron temperature is higher in the l(2) d(2) region. This is shown in Fig. 2 when a longitudinal field is applied.

If the length l(2) is sufficiently small (approximately

2 lambda (D) (see original) in an electric field of approximately 10/5/V/cm (for the material Si), a negative differential conductance, due to the above described differential conductance, due to the above-described effects, is present.

The structure can be fabricated with silicon on a sapphire substrate with appropriate high resolution (such as E-beam) lithographic techniques for l(1), l(2), d(1), d(2) definitions.

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