Device, made of a variety of semiconductors, incorporates three or more terminals. Between at least two terminals, switching action occurs. The other terminal pair performs either another switching function or a control function. This device is useful for computer-logic or memory applications

Holmstrom, F. R.

Rindner, W.

English

NASA Technical Reports Server

December 1970	 Brief 70-10448 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Multiport Semiconductor Devices 
(Back Contact) 
S Figure 1. Switching Diode Element; Schematic
	
Emitter	 Base 
	
I7	 Resistance Film	 I Jxxx_IL 
	
I	 Semiconductor
I
Substrate 
Collector 
Figure 2. The Terminals Connected

to a Transistor Curve Tracer 
Thin—Film Resistor 
Semiconductor 
The problem:	 between which a potential can be applied. Biasing the 
Design of devices, made of semiconductors, incor-	 diode, below but close to the threshold voltage, puts 
porating three or more terminals— multiportdevices 	 the diode in the high-resistance state. If a current 
that transform the signal applied to the input port	 now passes between the two terminals of the top 
into a suitable output signal. Semiconductor diodes 	 contact, heat generated adjacent to the active region 
are limited to applications calling for two-terminal 	 of the diode lowers the threshold voltage, permitting 
or one-port devices, 	 the device to switch to the low-resistance state. 
The solution:
	
	
Very small amounts of power suffice to heat the

extremely small volume and cause the switching. In A novel device, made of a variety of semiconductors, 	 fact, a small amount of control power can switch a including amorphous materials, incorporating three or greater amount of power. Thus the device provides 
more terminals. Between at least two terminals, switch- power gain with the control current applied to a ing action occurs such as in the double-injection 	 terminal other than that of the current being control-diode or in the "Ovonic" threshold switch. The other led. 
terminal pair may perform either another switching 	 The basic concept can be broadened considerably. function or a control function. The control function For example, the device may incorporate more than 
arises from either an electric-field effect or a thermal
one thermally active element; one heater may trigger 
effect or both.
several switching devices; or two or more switching 
How it's done:	 elements could be in such close proximity that they 
For concreteness, assume that the switching diode	 could trigger each other. 
element (Fig. 1) is a double-injection diode. The top	 The concept is not limited to crystalline semicon-
contact is a thin-resistive metal film with two terminals 	 ductor devices or metallic resistive elements; basically 
(eOntinued oserkal) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately ownedrights.
https://ntrs.nasa.gov/search.jsp?R=19700000432 2020-03-17T00:49:46+00:00Z
it encompasses all semiconductor switching devices, 
including amorphous semiconductor components in 
which threshold voltage is temperature-dependent, 
and where any thermal element can be incorporated 
for controlling the threshold voltage. 
Moreover, the concept covers devices that return 
spontaneously to the low-conductance state when 
voltage is removed, as well as memory-type devices. 
For the latter, the proper thermal cycling for switching 
of the device from the low- to the high-conductance 
state could be independent of the conductance-sensing 
operation; thus flexibility in design of memory sys-
tems would be greatly extended. 
The validity of the basic concept has been verified 
with an experimental device (Fig. 2) resembling that 
shown in Figure 1. One end of the heater was 
grounded, the other was biased negatively with succes-
sively greater values of bias current, and the current-
voltage behavior (between the back contact and 
ground) was plotted for each value of bias current. 
Although tentative, these results demonstrate that the 
structures described are readily reduced to practice.
Notes: 
This innovation may be useful for computer-logic 
or memory applications; it may interest designers 
or manufacturers of semiconductor devices. 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Headquarters 
National Aeronautics 
and Space Administration 
Washington, D.C. 20546 
Reference: TSP70- 10448 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code 200-1 LA 
Ames Research Center 
Moffett Field, California 94035 
Source: W. Rindner and F. R. Holmstrom of

Electronics Research Center

(E RC-10293) 
Brief 70-10448	 Category 01


Multiport semiconductor devices

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