sample="quota" bates="2026363725" isource="pm" decade="1990" class="ui" date="19920614" 6/14/92 [1:57pm] 02910\782\PAP\DCR\986.1 SECOND DRAFT PM-1668 ELECTRICALLY-POWERED SEMICONDUCTOR HEATER FOR FLAVOR GENERATING ARTICLES Background of The Invention This invention relates to articles in which flavor generating media are heated to release tobacco flavors. More particularly, this invention relates to electrical heaters for electrically heated flavor generating articles. An electrically heated flavor generating article is described in commonly-assigned United States Patent No. 5,060,671, which is hereby incorporated by reference in its entirety. That patent describes an electrically heated flavor generating article which is provided with a disposable set of electrical heating elements on each of which is deposited an individual charge of flavor generating medium containing, for example, tobacco or tobacco-derived material. The disposable heater/flavor unit is mated to a more or less permanent unit containing a source of electrical energy such as battery or capacitator, as well as control circuitry to actuate the heating elements in response to a puff by a consumer on the article or the depression of a manual switch. The circuitry is designed so that at least one but less than all of the heating elements are actuated for any one puff, so that a predetermined number of puffs, each containing a premeasured amount of flavor-containing substance, is is relatively low (e.g., about 2.3 g/cm³ to 2.6 g/cm³ at 27ºC), the flavor generating articles made with the electrical heaters of the present invention can be light in weight and will heat up quickly and efficiently transfer heat to the flavor generating medium. Although FIG. 1 shows the electrical resistivity of silicon for only two types of dopant impurities -- phosphorous atoms and boron atoms --, it is understood that other dopants could as well be used. For example, alternate dopants might include antimony . and [PLEASE LIST ALL DOPANTS POSSIBLE]. As used herein, the term "dopant impurity" is defined to mean any substance, particle, defect, or vacancy or complex, or the like, or any combination thereof, that is capable of altering the electrical resistivity of the semiconductor material through its incorporation therein. The only restrictions on the types of dopant impurities that can be used are that they must provide an electrical resistivity in a range that allows the heater to achieve a surface temperature from about 350ºC to about 900ºC when in contact with a flavor generating medium in a flavor generating article, and they must have a low enough reactivity to avoid toxicological or other reactive effects. Alternatively, an encapsulant, such as ceramic or the like, can be employed if the reactivity of the doped silicon is too high at the expected operating temperatures. Suitable materials for encapsulation of the heaters include silica, alumina, and sol gels, and . Additionally, a protective layer of SiO2 or some other silicon-based oxide (SiOx) can be provided on the surface of the silicon heater to serve as encapsulant. What ever type of dopant is used, it can be incorporated into the silicon semiconductor material using any known method. Preferably, it is incorporated into the silicon during initial crystal growth. However, it can also be added at a later stage by, for example, diffusion, epitaxial processes, or ion implantation processes. Although it is preferably that the dopant impurities of the present invention be substantially uniformly distributed throughout the bulk of the silicon semiconductor material, this does not have to be the case. It will be understood that other dopant profiles could also be used to achieve a graded or other non-uniform composition. For example, profiles with dopants concentrated near a surface could be used to provide high surface concentration of electrical conduction, and thus heat generation. Although FIG.1 shows the electrical resistivity for only silicon as a function of dopant impurity concentration, it will be apparent that other semiconductors could as well be used to fabricate the heater of the present invention. The only restrictions on the types of semiconductor materials that can be used, as is the case with dopant impurities, are that they must provide an electrical resistivity in a range that allows the heater to achieve a surface temperature from about 350ºC to about 900ºC when in contact with a flavor generating medium in a flavor generating article and they must have a low enough reactivity to avoid toxiciological or other reactive effects. In accordance with the principles of the present invention, a variety of electrical heaters having dimensions of about 14-16 mm in length, about 1.5 mm in width and about 0.36 mm (14 mils) in thickness, have been fabricated out of silicon doped with phosphorous at levels resulting in electrical resistivities of approximately 4.3 x 10 . These heaters had resistances of approximately 1.2 . One second pulses at potentials of about 4.5 volts across these heaters produced surface temperatures ranging from about 500ºC to about 700ºC in still air. Although the heater of the present invention has been discussed above with reference to FIGS. 2-5, wherein the flavor generating material is preferably in intimate thermal contact with the heater, this does not have to be the case. For example, the heater of the present invention can be placed adjacent a source of liquid flavor generating material that is brought into contact with the heater. Thus it is seen that an electrical heater for use in flavor generating articles is provided. One skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration and not of limitation, and the present invention is limited only by the claims which follow. WHAT IS CLAIMED IS: 1. A heater for heating a flavor generating medium for delivering to a consumer a flavor-containing substance, the heater comprising semiconductor material. 2. The heater of claim 1 wherein the semiconductor material is doped with dopant impurities to provide a predetermined electrical resistivity. 3. The heater of claim 2 wherein the dopant impurities are a n-type dopant. 4. The heater of claim 3 wherein the heater has a resistance of between about 0.5 and about 3.0 . 5. The heater of claim 4 wherein the heater has a resistance of between about 1.0 and about 1.6 . 6. The heater of claim 5 wherein the heater is substantially rectangular. 7. The heater of claim 2 wherein the dopant impurities are a p-type dopant. 8. The heater of claim 7 wherein the heater has a resistance of between about 0.5 and about 3.0 . 9. The heater of claim 8 wherein the heater has a resistance of between about 1.0 and about 1.6 10. The heater of claim 9 wherein the heater is substantially rectangular. 11. The heater of claim 2 wherein the semiconductor material is non-uniformly doped with dopant impurities to provide a predetermined electrical resistivity profile. 12. The heater of claim 11 wherein the heater has a resistance of between about 0.5 and about 3.0 . 13. The heater of claim 12 wherein the heater has a resistance of between about 1.0 and about 1.6 14. The heater of claim 12 wherein the heater is substantially rectangular. 15. The heater of claim 1 wherein the semiconductor material is silicon. 16. The heater of claim 15 wherein the silicon semiconductor material is doped with dopant impurities to provide a predetermined electrical resistivity. 17. The heater of claim 16 wherein the dopant impurities are a n-type dopant. 18. The heater of claim 17 wherein the n-type dopant impurities are phosphorus impurities. 19. The heater of claim 18 wherein the silicon semiconductor material is doped with phosphorus impurities to a level in the range of between about 1 x 10 impurities/cm³ and about 1 x 10 impurities/cm³. 20. The heater of claim 19 wherein the heater has a resistance of between about 0.5 and about 3.0 21. The heater of claim 20 wherein the heater has a resistance of between about 1.0 and about 1.6 22. The heater of claim 19 wherein the silicon semiconductor material is doped to a level in the range of between about 5 x 10 impurities/cm³ and about 5 x 10 impurities/cm³. 23. The heater of claim 22 wherein the heater is substantially rectangular. 24. The heater of claim 16 wherein the dopant impurities are a p-type dopant. 73. The article of claim 72 wherein the silicon semiconductor material is doped with dopant impurities to provide a predetermined electrical resistivity. 74. The article of claim 73 wherein the dopant impurities are a n-type dopant. 75. The article of claim 74 wherein the n-type dopant impurities are phosphorus impurities. 76. The article of claim 75 wherein the silicon semiconductor material is doped with phosphorus impurities to a level in the range of between about 1 x 10 impurities/cm³. 77. The article of claim 76 wherein the heater has a resistance of between about 0.5 and about 3.0 . 78. The article of claim 77 wherein the heater has a resistance of between about 1.0 and about 1.6 . 79. The article of claim 76 wherein the silicon semiconductor material is doped to a level in the range of between about 5 x 10 impurities/cm³ and about 5 x 10 impurities/cm³. 80. The article of claim 79 wherein each of the plurality of heaters are substantially rectangular. 81. The article of claim 71 wherein said source of electrical energy comprises a battery. [ 82. The article of claim 81 wherein the batteries are rechargeable 8 2 3. The article of claim 71 wherein the heater base is substantially cylindrical and each of the plurality of electrical heaters has two opposing flat surfaces defining a plane, wherein the heaters are 5 arranged with their respective planes aligned radially outward from the center of said cylinder. 8 3 4. The article of claim 71 wherein the heater base is substantially cylindrical and each of the plurality of electrical heaters has two opposing flat surfaces, wherein the heaters are arranged 5 circumferentially so that the flat surfaces are along the periphery of the heater base. 8 4 5. The article of claim 8 3 4 wherein the flavor generating medium is disposed adjacent the flat surfaces of the heaters facing the inside periphery of the heater base. 8 5 6. The article of claim 8 3 4wherein the flavor generating medium is disposed adjacent the flat surfaces of the heaters facing the outside periphery of the heater base. 8 6 7. The article of claim 73 wherein the dopant impurities are a p-type dopant. 8 7 8. The article of claim 8 6 7 wherein the p-type dopant impurities are boron impurities. 8 8 9. The article of claim 8 7 8 wherein the silicon semiconductor material is doped with boron impurities to a level in the range of between about 1 x 10 impurities/cm³ and about 1 x 10 5 impurities/cm³. 89 90. The article of claim 8 8 9 wherein the heater has a resistance of between about -.5 and about 3.0 . 9 0 1. The article of claim 89 90 wherein the heater has a resistance of between about 1.0 and about 1.6 . 9 1 2 . The article of claim 8 8 9 wherein the silicon semiconductor material is doped to a level in the range of between about 5 x 10 impurities/cm³ and about 5 x 10 impurities/cm³. 9 2 3. The article of claim 9 1 2 wherein each of the plurality heaters are substantially rectangular. 9 3 4. The article of claim 73 comprising eight semiconductor electrical heaters so as to provide eight discrete heating regions to heat the flavor generating medium. ELECTRICALLY-POWERED SEMICONDUCTOR HEATER FOR FLAVOR GENERATING ARTICLES Abstract of the Disclosure An electrical heater for use in electrically- 5 heated flavor generating articles is provided. The heater is made from silicon or some other type of semiconductor material doped with n-type or p-type impurities to provide a predetermined electrical resistivity. When incorporated into flavor generating 10 articles and made from silicon semiconductor material, such heaters can have resistances in the range of from about 0.5 to about 3 and are able to achieve operating temperatures in the range of from about 350ºC to about 900ºC, when in contact with flavor generating 15 material, by pulsing with short-duration low-voltage pulses. An electrical heater unit containing a plurality of the heaters is also provided. Additionally, a flavor generating article containing the electrical heater unit is provided.