SEMICONDUCTOR CONSTRUCTION UNIT

The invention concerns a semiconductor construction unit, with the which half] pus ranges following in a substrate is trained: a) a first semiconductor range of a first type of conductivity; b) a second semiconductor range of second, to the first opposite type of conductivity, which surrounds the first semiconductor range under formation of a first pn transition within the semiconductor construction unit completely; c) third ttalbleiterbereich of the first type of conductivity, which surrounds second under formation of a second pn transition ttalbleiterbereich within the semiconductor construction unit completely, whereby the first, second and third semiconductor range is trained with a connection electrode in each case, and d) more trained in the first semiconductor range a fourth semiconductor range of the first type of conductivity, which with the first semiconductor range of the first type of conductivity, which forms a transition with sudden change in the carrier concentration with first ttalbleiterbereich, whereby on polarity of the first pn transition to passage direction majority charge carriers walk from the first semiconductor range by second into the third semiconductor range, which possesses fourth semiconductor range an impurity concentration, which is substantially higher than those of the first semiconductor range, and which thickness of the first semiconductor range smaller as the diffusion length of the Minoritätsladungsträger in this semiconductor range is. It was usual so far to manufacture transistors with a highly endowed emitter range. It is also already a transistor well-known for high frequency enterprise, which exhibits a small impurity concentration in the emitter, Basiselektrodenund collector range. A Beispie! but is descriptive in the US-PS Nr.3, 591.430. In addition in this prior publication one suggests, a substantial part of the emitter range with a range of high Verunz5 retnigungskonzentration and likewise to the Kol! to cover ektorbereich with a second range of high impurity concentration. In the US patent specification mentioned it is not described however that the diffusion length or diffusion depth of the minority carriers must be larger A! s the width and/or width of the emitter range, nor is there implemented that the minority carriers reflected by the inserted field are to essentially adjust the injected minority carrier diffusion current, which flows from the basis by the emitter. The US patent specification does not teach also, how the final profile or the distribution of the impurity concentration should be constituted, nor is said, which width and/or width the basis or the emitter to exhibit to be supposed. Also nothing is implemented over the conditions for epitaxiale growth (for example temperature or amounts of precipitation and speeds). It is only something mentioned over the Vordiffusionsbedingung, from which however no conclusion and no picture let themselves win over the final structure. During the production of conventional bipolar transistors it was usual so far for the training of the emitter basis transition to use a double diffusion technology. From the theoretical point of view, and due to of attempts, the impurity concentration for the emitter is more highly selected than for the basis. If this difference becomes larger, then also the emitter effectiveness or the emitter efficiency becomes larger and approaches more and more the value unity. A high doping however increases the lattice defects and transfers in the semiconductor substrate. As consequence of a strong doping the diffusion length of the Minorltätsträger within the endowed range drops. A degradation of the doping, according to the early the well-known execution forms “5 of transistors, leads on the other hand to dropping the reinforcement degree. An l {albleiterbauteil the initially mentioned kind is become known e.g. by the DE-OS 1090329, the US-PS Nr.2, 822.310 and the FR-PS Nr.2.130.399. With these well-known semiconductor construction units however no special vote of the individual layer thicknesses and the diffusion length of the minority carriers was planned. With the semiconductor construction unit in accordance with the DE-OS 1090329 it is intended that by the impurity concentration of the adjacent layers exhibiting the same type of conductivity determined built-in voltage is selected in such a way that it is proportional the sum of the logarithms of the two impurity concentrations. The disadvantage of this solution is in that in this transient area only a relatively modest barrier develops itself. Also with these proposals from there the problems described above can be reduced only in a very modest extent. The invention is the basis the task to suggest to one regarding its characteristic S of characteristic values substantially improved semiconductor construction unit which is characterised particularly by a completely substantially increased current amplification factor with strongly improved intoxication characteristic values. It is meant thereby particularly of a semiconductor construction unit with multiple transitions, which at the same time exhibits with small, thermally caused characteristic value deviations a high breakdown voltage. Finally it should be the goal of the invention, to lay out which semiconductor construction unit which can be created in such a way that the production and the employment are applicable as integrated circuit as well as conventional transistors, including the complementary transistors. From there with a semiconductor construction unit it is planned according to invention that the difference between impurity concentration of the first and fourth semiconductor range amounts to at least two powers of ten, so that to this difference the energy barrier due is appropriate for the impurity concentration more highly than the energy level of the Minoritätsladungsträger reaching from the second semiconductor range into the first semiconductor range injected and the transition with sudden change in the carrier concentration, and that the sum of thickness of the first and fourth semiconductor range is smaller than the diffusion length of the Minoritätsladungsträger in the first semiconductor range. By these measures a field is formed, which causes that the z0 is essentially flat process of the injected minority carrier concentration over the emitter. Thus it is reached that the drift stream produced by this field essentially adjusts the minority carrier diffusion current injected by the base region. In addition the impurity concentration of the collector range can be low selected, in order to ensure a high breakdown voltage. For conventional transistors it is accepted that the minority carrier diffusion length lies in the order of magnitude of 1 to 2 m. For the semiconductor construction units with multiple transitions after the invention against it the minority carrier diffusion length amounts to 50 to 100 M. The current amplification factor of a conventional transistor is usually with approximately 500, while with the semiconductor construction unit after the invention values of 3000 or more can be reached. Because in the emitter a transition between easy and highly endowed ranges are intended by the same type of conductivity, a drift stream lets itself obtain, which essentially adjusts the minority carrier diffusion current. The invention is more near described now on the basis the designs. Show: Fig.1 a schematic partial section opinion of an NPN transistor with characteristics after the invention; Fig.2 3s a example-wise impurity profile. for the semiconductor construction unit after Fig.1 as well as the representation of the minority carrier concentration within the emitter range; Fig.3 a partial section opinion of an integrated circuit, which exhibits an NPN transistor with characteristic according to invention and additionally a conventional PNP transistor, which form a pair of transistor complementary; Fig.4 the diagram of the emitter mass current reinforcement (h FE) as function of the Kollektorstroms; Fig.5 the diagram of the noise factor as function of the frequency with a feed impedance of 1000 ohms; Fig.6 the diagram of the noise factor as function of the frequency with a feed impedance of 30 ohms and Fig.7 the diagram of noise factor characteristics as function of the Kollektorstroms. As example of a preferential execution form of the invention first on the basis of Fig.1 an NPN transistor is described. Reference symbol --l-- a substrate endowed highly with N-leading impurities marks --1-- particularly a silicon substrate endowed highly with antimony. The Dotierungskonzentratlon is preferably about 4 x 10 s cm-3 this results in a resistivity of for instance 0,0l cm. It was determined that this doping can vary between 0,008 and 0,012 cm. The thickness of the substrate preferably is with approximately 250 M. On the substrate --1-- becomes one together with that N+-leading substrate --1-- as collector N which can be used--leading silicon epitaxial region --2-- trained. This epitaxial region --2-- is relatively easily with antimony endowed to receive sufficiently in order an impurity concentration from 7 x 10” cm-3. The resistivity is with approximately 8 to 10 cm. The epitaxial region is preferably about 20 m thickly. The production of an active basis for the transistor becomes then on the N--leading layer --2-- a P--leading silicon epitaxial region --3-- trained. For doping Ber can be inserted into -3 of such quantity that an impurity concentration of 1 x 10 1 “cm results. The resistivity amounts to 1.5 n cm. The thickness of the layer --3-- lies with approximately 5; in. The production of an emitter becomes then on the P--leading layer --3-- a silicon - epitaxial region --4-- trained by the N-type. The layer --4-- is relatively small with antimony endowed, whereby the impurity concentration is with approximately 5.5 × 10, 5 cm-3. The resistivity amounts to about 1 n cm. The thickness of the layer --4-- lies with approximately 2 to 5 M. Subsequently, a diffusion layer 5 is produced of the N+-leading type under high doping with phosphorus. This diffusion layer has a surface impurity concentration of approximately 20 cm-3 and a thickness of approximately 1.0 M. A N-leading diffusion layer endowed highly with phosphorus --6-- surrounds so far, descriptive NPN transistor. IS the doping amounts to about 3 x 10, 9 cm-3 as surface concentration. This doping penetrates through the P--leading layer --3-- into N' the leading layer --2-- to the N+-leading range --1-- the substrate is reached. It surrounds with it the base region --3--. As leading connection to the base region --3-- becomes P-leitender range --7--, which is obtained by diffusion, intended. The range --7-- is with Ber and a concentration of approximately 3 x 10 *” cm-3 at the surface endowed. The diffused range --7-- penetrates through the N--leading layer --4-- into the P--leading basis layer --3--, those the emitter range -.4-- limited and surrounds. Diffused P-leitender range --8-- forms the basis contact range and consists of a range endowed highly with Ber. The impurity concentration at the surface amounts to -3 about 5 x I0 " cm at the lower surface of the substrate --I-- becomes a collector electrode --9-- from aluminum trained. On the basis contact basis --8-- becomes a base electrode --10-- from aluminum applied. On the highly endowed emitter range --5-- becomes a Emitterelektrode --ii-- from aluminum trained. The passivation the upper surface of the device becomes by a silicon dioxide layer --67-- taken off. As result of the so far described structure it shows up that the N--leading layer --2-- and the P--leading layer --3-- a collector basis transition --12-- form. The P--leading layer --3-- and the N--leading layer -.4-- form an emitter basis transition --13--, 3S during between the N--leading layer --4-- and the N+-leading layer --5-- a transition --14-- from easier on high doping of the same type of conductivity (called in the further briefly LH transition) develops. The width or width incoming goods between the emitter basis transition --13-- and the LH transition --14-- about 6 t amount to. Fig.2 illustrates the impurity profile and the minority carrier concentration in the emitter of the so far described semiconductor construction unit. The top of the Fig.2 illustrates the relative position of emitter, basis and collector. The middle part of the diagram shows the impurity concentration in flavours per cubic centimeter, measured from (according to characterized) the outside surface to the substrate range --1--. The lower part of the designs clarifies the relative portion of the Mineritätsträgerkonzentration in different enriched, to 4S beginning with that N÷ leitendenBereich --5-- over the emitter range --4--. If the minority carrier diffusion length is smaller than the width of the emitter (incoming goods), then results the minority carrier profile shown by the strichlierte line (A). It is formed a field, whereby a minority carrier concentration process, how it is shown by the strichlierte line (B), results. s0 a semiconductor construction unit with this structure suggests a high hFE value with low noise. In order to describe the reasons for this result, it is mentioned that the emitter current reinforcement (h FE) is one of the substantial parameters of the transistor. - G - This parameter generally defined too: hFE = (1) 1 - A No. 376844 where The basis - Stromverstärkung designates (with purchase of the basis to mass). The Stromverstärkung A results too: (z = a*. B.u where with a* the collector multiplication relationship, B a basis transportation factor, emission efficiency of the emitter (emitter efficiency) are named • for an NPN transistor for example arises the emitter efficiency v too: Jn 1 U = Jn + Jp I + Jp/Jn (2) with (3) where with Jn the Elektronenstromdiehte is marked, which see due to the electrons injected by the emitter by the emitter basis transition to the basis results in and a hole current density marks Jp, due to of holes injected in reverse direction of the basis over the same transition to the emitter arises • the electron flow density Jn is given too: qv q. DP. NP -- Jn (e kT - I) (4) LN the hole current density Jp is given too: q • DP. pn Jp - LP qv kT • (e -1) (5) therein are marked with LN the electron diffusion length in the P-leading basis, with LP the hole diffusion length in the N-leading emitter, with DN the electron diffusion constant, with Dp the hole diffusion constant, with NP the minority electron concentration in the P-leading basis in the equilibrium, with pn the minority hole concentration in the N-leading emitter in the equilibrium, with v the tension, with T the temperature, lining up applied, between the emitter basis transition and/or, with q the load of an electron and with k the Boltzmann constant. A value ö as the relationship of Jp and Jn lets itself indicate then: “= Jp _ LN D__p pn (6) Jn LP DN NP in addition this relationship lets itself represent as: W I) p N.A (- _ _ _ _ LP DN N D (7) thereby the indicated relationship lets itself through to replace: No. 376844 pns WELL NP N D where with WELL the impurity concentration of the base region, with lp the impurity concentration of the emitter range and with W the base width or - width designation is limited, the electron diffusion length LN in the base region. The carrier diffusion constants DN and Dp are functions of a carrier mobility and the temperature and can as essentially constant be accepted. With the construction unit represented in Fig.1 is the easily endowed emitter --4-- between the emitter basis transition --13-- and the LH transition --14-- trained, so that the value of the hole diffusion length becomes very large LP. Under the condition that the easily endowed emitter --4-- for example an impurity concentration of 5,5 × 10 ' 5 cm-3 exhibits and the produced epitaxial region in good lattice condition is present, the value for LP about 50 to 100 m will amount to. In the case of a conventional transistor against it because of recombination under the emitter surface only a minority carrier diffusion length in the emitter arose, which would be same or smaller than the width VE of the emitter range. A substantial characteristic of the invention is seen thus that the minority carrier diffusion length is larger THOSE of the emitter than the width or width incoming goods between the emitter basis transition and the LH transition in the easily endowed emitter. As the further important factor of the invention it is to be mentioned that the LH transition --14-- in the easily endowed emitter --4-- lies. This LH transition --14-- a so-called “inserted field” forms in the emitter, which acts in such direction that the hole current of the emitter basis transition --13-- against this transition --14-- flows. If the inserted field of the LH transition is large enough, then the diffusion current of the holes is compensated and becomes approximate equal the drift stream of the holes by the field in the easily endowed emitter --4--. This compensation causes a dropping of the hole current Jp, that from the basis by the emitter basis transition --13-- into the easily endowed emitter --4-- one injects. With the subject of the invention the “inserted field” changes the equation (5) as follows: qv p -- Incoming goods J'p = q. DP. (e kT-1). tanh ( -- ) LP LP (hereunder applies the condition LP” incoming goods) qv pn incoming goods (input clutch -1) (8) J'p -- q. Dp L p q¢ the difference of potential of the inserted field is large there and ekT” 1 is valid, (for example incoming goods qO - 10; 0 = 0.2 V) and further by the large LP the value -- , arises kT L2p becomes very small as result that J'p reaches approximate zero. Dropping Jp causes that empties u in accordance with equation (3) unity becomes approximate, during the value A according to equation (2) largely and the value h FE according to equation (1) becomes likewise very large. The very low intoxication characteristic values can be explained as follows: The lattice defect or the transfer, there the emitter basis transition is strongly lowered --13-- by an easily endowed emitter --4-- and a likewise easily endowed basis --3-- are formed, the impurity concentration of the easily endowed emitter --4-- if value should be limited, smaller is than 10 " cm another factor with consideration of the intoxication characteristic values, for the life span • and the minority carrier diffusion length LP on one ungeP -3 ferries, which leads to a small noise level, it is to be found in the fact that the emitter current in the easily endowed emitter --4-- and in the likewise easily endowed basis --3-- essentially in vertical direction flows. The LH transition is as mentioned, between the easily endowed and highly endowed Bele is enough trained by the same type of conductivity. The LH transition is for Mineritätsträger to a large extent undurchdringbar, not however for " the Majoritätsträger. The high emitter current reinforcement (hFE) is represented in Fig.4. The difference between the curves 15 and 16 results only from a different planar arrangement. Both curves however clarify a very high emitter current amplification factor (emitter to mass referred). The line 17 in Fig.5 clarifies the intoxication behavior as function of the frequency for the semiconductor construction unit illustrated in Fig.1. The line 18 against it (likewise Fig.5) shows the intoxication characteristic values for a conventional semiconductor construction unit with the lowest well-known intoxication values. The lines 19 and 20 in Fig.6 show one the Fig.5 comparable representation, however with different feed impedance. an intoxication value diagram, whereby the line 21 itself on a well-known, shows 2 {) Fig.7 good semiconductor construction unit refers, compared with an intoxication characteristic 22 with the subject of the invention, for example after the execution form in accordance with Fig.1. The lines 21 and 22 are referred thereby to a noise factor with 3 railways. Which lies within the essentially parabolförmigen curve, is below 3 railways. It lets itself state thus that the Fig.4, 5, 6 and 7 for the subject of the invention a completely substantial in relation to improvement that so far admitted to semiconductor construction units to make clear. Fig.3 shows a second remark example of the invention, with which on the basis NPN transistor described by Fig.1 into an integrated circuit, together with to one or more other semiconductor elements, for example with a PNP transistor of conventional Bau3D kind is inserted. These two elements form complementary a pair of transistors. In a P-leading substrate --30-- is an NPN transistor --31-- trained in on the basis way described by Fig.1. A highly endowed collector is enclosed --1--, an easily endowed collector --2--, an easily endowed basis --3--, an easily endowed emitter --4--, a highly endowed range --5--, a collector exchange area --6--, a collector contact range --15--, a base terminal range --7--, a B isiskontaktbereich --8--, a collector electrode --9--, a base electrode --10-- and a Emitterelektrode --11--. In the same substrate --30-- is a conventional PNP transistor --32-- trained, that from a P--leading collector --63--, a N--leading base layer --64--, a P+-leading emitter --38--, a P-leading Kollektoranschluß --37--, a P-leading collector contact range --48--, 0 a N+-leading basis contact range --35--, a collector electrode --39--, a base electrode --40-- and a Emitterelektrode --41-- exists. Bie both transistors --31 and 32-- are electrically against each other insulating by pn transitions. P-leitender isolation range --50-- is with the substrate --20-- connected and the two NPNund surround PNP transistors --31 and/or 32--. Three N-leading ranges --61, 62 and 66-- form becherförmigen 5 richly, for that the PNP transistor --32-- surrounds. In this integrated circuit a multiplicity of pairs or trios is formed at the same time. For example the N+-leading ranges become --1 and 61-- by selective diffusion in the P-leading substrate --30-- manufactured. The N--leading ranges --2 and 62-- by epitaxiales growth are produced. The P--leading range --3--, that the basis of the NPN transistor --31-- and the range --63--, that the collector of the PNP transistor --32-- forms, by epitaxiales growth or by selective diffusion are manufactured. The N--leading range --4-- (the easily endowed emitter of the NPN transistor) and the range --64--, the basis of the PNP transistor, by epitaxiales growth are produced. The N+-leading ranges --6 and 66-- by diffusion are manufactured. The P-leading ranges --7 and 37-- by diffusion are produced. The P+-leading ranges --8, 38 and 48-- by diffusion are produced. The N+-leitendenBereßche: --6-- (the emitter of the NPN transistor), --15-- (the collector contact range of the NPN transistor) and --35-- (the basis contact range of the PNP transistor) by Difussion are manufactured. The expression “essentially flat”, which was used for the characterisation of the condition of the minority carrier concentration over the active emitter range, is to be understood in such a way that the summarized value of the minority carriers injected by the active base region into the active emitter range and due to the inserted field the minority carrier in the emitter, moving in reverse direction, result over the active emitter range a relatively flat process. This condition is characterized for the emitter range by the line (C) in Fig.2, which runs in the wesentiiehen horizontal. While the invention was described with reference to Fig.1 on the basis an NPN transistor, it was not missed to mention that in appropriate way also a PNP transistor with comparable structure and comparable characteristic values lets itself manufacture. Also on the production of a semiconductor thyristor of the NPNP type the invention lets itself use in favourable way. That with the invention a semiconductor construction unit with Mehrfaehübergängen and a very high current amplification factor was created, to the one low impurity concentration within the emitter range, the width of the emitter lets itself exceeding injected minority sträger diffusion length, a low Oberfl recapitulatory determine ächenrekombin ationsgeschwindigkeit and a good crystal lattice exhibits. The descriptive preferential execution form of the invention exhibits a range of high impurity concentration of the same type of conductivity as the emitter, which covers at least one part of the emitter range and forms a LH transition, which leads minority carriers as drift stream back to the base region. The arrangement is so met that the drift stream the minority carrier bordering on the LH transition - diffusion current essentially eliminates, which is injected from the base region, since it is in reverse arranged. are: