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US 3,971,056 AGranted
Semiconductor temperature switches
AssigneeCutler-Hammer, Inc.
InventorsStanley V. Jaskolski, Robert W. Lade, Herman P. Schutten, Gordon B. Spellman, Lawrence E. Van Horn
Life of this patent
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Abstract
Germanium semiconductor temperature switches are described which are capable of intrinsically switching between high and low resistance states within a temperature range up to 55.degree.C, and are adapted for operating at voltages up to 400 volts. These temperature switches are disclosed in various configurations. Basic circuits for adjusting the temperatures at which such switches switch within a range are disclosed. Preferred methods of making the same are also disclosed.
Claims45
A semiconductor temperature switch actuatable at a predetermined temperature within a temperature range up to about 55.degree.C and adapted for operating at voltages up to about 400 volts, comprising a semiconductor device formed of first, second, third and fourth layers defining therebetween first, second and third junctions:
- said first layer being of one conductivity type of germanium and having a first current-carrying electrode attached thereto;
- said second layer being a thin stratum of opposite conductivity type of germanium with a transfer efficiency of minority charge carriers thereacross of at least about 50%;
- said third layer being of said one conductivity type of germanium and having a resistivity greater than 0.01 ohm-centimeter and a minority carrier diffusion length, L.sub.d, between about 0.5 mils and about 5 mils, and a thickness equal to between about 0.1 L.sub.d and about 10L.sub.d ;
- said fourth layer being of said opposite conductivity type and having a second current-carrying electrode attached thereto;
- said first junction having an injection efficiency of charge carriers into said second layer between about 50% and about 90%;
- said second junction having a breakover voltage essentially equal to said operating voltage at said predetermined switching temperature within said temperature range when a voltage is applied to said electrode on said first layer with respect to said electrode on said fourth layer of such polarity as to reverse bias said second junction, and a low impedance subsequent to said switching at said predetermined temperature when said second junction becomes forward biased;
- and
- said third junction having an injection efficiency of charge carriers into said third layer of at least about 80%;
- whereby when said switch reaches said predetermined temperature, said second junction changes from a reversed biased to a forward biased junction to permit a marked increase in the flow of current therethrough.
6 more elements
A bilateral semiconductor temperature switch actuatable at a predetermined temperature up to about 55.degree.C and adapted for operating with voltages of alternating polarity up to about 400 volts, comprising two semiconductor assemblies, each of which is formed of first, second, third and fourth layers defining therebetween first, second and third junctions;
- said assemblies being arranged to form an integrated device wherein said third layer is common to both of said assemblies and said second layer of one of said assemblies and said fourth layer of said other of said assemblies are contiguous to one side of said common third layer and said fourth layer of said one of said assemblies and said second layer of said other of said assemblies are contiguous to the other side of said third common layer;
- said first layer of each of said assemblies being of one conductivity type of germanium and having a first current-carrying electrode attached thereto;
- said second layer of each of said assemblies being a thin stratum of opposite conductivity type of germanium with a transfer efficiency of minority charge carriers thereacross of at least about 50%;
- said third common layer of said assemblies being of said one conductivity type of germanium and having a resistivity greater than 0.01 ohm-centimeter and a minority carrier diffusion length, L.sub.d, between about 0.5 mils and about 5 mils, and a thickness equal to between about 0.1 L.sub.d and about 10 L.sub.d ;
- said fourth layer of each of said assemblies being of said opposite conductivity type germanium and having a second current-carrying electrode attached thereto;
- said first junction of each of said assemblies having an injection efficiency of charge carriers into said second layer between about 50% and about 90%;
- said second junction of each of said assemblies having a breakover voltage essentially equal to said operating voltage at said predetermined switching temperature within said temperature range when a voltage is applied to said electrode on said first layer with respect to said electrode on said fourth layer of such polarity as to reverse bias said second junction, and a low impedance subsequent to said switching at said predetermined temperature when said second junction becomes forward biased;
- and
- said third junction of each of said assemblies having an injection efficiency of charge carriers into said common third layer of at least 80%;
- said first electrode of said one assembly and said second electrode of said other assembly being connected to a first common lead and said second electrode of said one assembly and said first electrode of said other assembly being connected to a second common lead;
- whereby when said switch reaches said predetermined temperature, said second junctions alternately change from reversed biased to forward biased junctions to permit a marked increase in the flow of current therethrough.
8 more elements
A temperature-controlled electrical circuit operable at temperatures up to about 55.degree.C, comprising in combination
- a. d.c. voltage source means;
- b. d.c. motor means;
- c. semiconductor temperature switch means responsive to the temperature of an associated environment and arranged to actuate said motor means at a predetermined switching temperature within said range, said switch means comprising a semiconductor device formed of first, second, third and fourth layers defining therebetween first, second and third junctions;
- said first layer being of one conductivity type of germanium and having a first current-carrying electrode attached thereto for connection to one side of said voltage source means;
- said second layer being a thin stratum of opposite conductivity type of germanium with a transfer efficiency of minority charge carriers thereacross of at least 50%;
- said third layer being of said one conductivity type of germanium and having a resistivity greater than 0.01 ohm-centimeter and a minority carrier diffusion length, L.sub.d, between about 0.5 mils and about 5 mils, and a thickness equal to between about 0.1 L.sub.d and about 10L.sub.d ;
- said fourth layer being of said opposite conductivity type and having a second current-carrying electrode attached thereto for connection to the other side of said voltage source means through said motor means;
- said first junction having an injection efficiency of charge carriers into said second layer between about 50% and about 90%;
- said second junction having a breakover voltage essentially equal to the voltage across said switch at said predetermined switching temperature when said voltage is applied to said electrode on said first layer with respect to said electrode on said fourth layer of such polarity as to reverse bias said second junction, and a low impedance subsequent to said switching at said predetermined temperature when said second junction becomes forward biased;
- and
- said third junction having an injection efficiency of charge carriers into said third layer of at least about 80%;
- whereby when said switch means reaches said predetermined temperature said motor means is actuated.
9 more elements
A temperature-controlled electrical circuit operable at temperatures up to about 55.degree.C, comprising in combination
- a. a.c. voltage source means;
- b. a.c. motor means
- c. bilateral semiconductor temperature switch means responsive to the temperature of an associated environment and arranged to actuate said motor means at a predetermined switching temperature within said range, said switch means comprising two semiconductor assemblies, each of which is formed of first, second, third and fourth layers defining therebetween first, second and third junctions;
- said assemblies being arranged to form an integrated device wherein said third layer is common to both of said assemblies and said second layer of one of said assemblies and said fourth layer of said other of said assemblies are contiguous to one side of said common third layer and said fourth layer of said one of said assemblies and said second layer of said other of said assemblies are contiguous to the other side of said third common layer;
- said first layer of each of said assemblies being of one conductivity type of germanium and having a first current-carrying electrode attached thereto;
- said second layer of each of said assemblies being a thin stratum of opposite conductivity type of germanium with a transfer efficiency of minority charge carriers thereacross of at least about 50%;
- said third common layer of said assemblies being of said one conductivity type of germanium and having a resistivity greater than 0.01 ohm-centimeter and a minority carrier diffusion length, L.sub.d, between about 0.5 mils and about 5 mils, and a thickness equal to between about 0.1 L.sub.d and about 10 L.sub.d ;
- said fourth layer of each of said assemblies being of said opposite conductivity type germanium and having a second current-carrying electrode attached thereto;
- said first junction of each of said assemblies having an injection efficiency of charge carriers into said second layer between about 50% and about 90%;
- said second junction of each of said assemblies having a breakover voltage essentially equal to the voltage across said switch means at said predetermined switching temperature when a voltage is applied to said electrode on said first layer with respect to said electrode on said fourth layer of such polarity as to reverse bias said second junction, and a low impedance subsequent to said switching at said predetermined temperature when said second junction becomes forward biased;
- and
- said third junction of each of said assemblies having an injection efficiency of charge carriers into said common third layer of at least 80%;
- said first electrode of said one assembly and said second electrode of said other assembly being connected to a first common lead connected to one side of said voltage source means and said second electrode of said one assembly and said first electrode of said other assembly being connected to a second common lead connected to the other side of said voltage source means through said motor means;
- whereby when said switch reaches said predetermined temperature, said motor means is actuated.
11 more elements
Dependencies are inferred from the claim text.