DE1285625C2 - METHOD FOR MANUFACTURING A SEMICONDUCTOR COMPONENT - Google Patents

Description

The invention relates to a method for producing a semiconductor component with a semiconductor body, in the at least one semiconductor circuit element with at least two zones with different Conduction properties is formed in which on one of the large surfaces of an Ausianss semiconductor body Semiconductor material from the vapor phase is grown epitaxially and for the semiconductor circuit element required zones are formed in the grown semiconductor material will.

Zones with different conductivity properties are defined as zones with different conductivity and / or understood with different conductivity types.

In the known method -: ur production of planar semiconductor components, a surface of an output semiconductor body is provided with a masking layer, often a silicon oxide layer. covered and then for the semiconductor circuit element or elements required zone by diffusion of impurities into the output semiconductor body generated by openings made in the oxide layer. This procedure has the important advantage that the surface of the semiconductor body remains flat and protected by the oxide layer will. The disadvantage is that the concentration ar. Impurities in the starting semiconductor body or must be overdoped in an already formed zone when an impurity diffuses and that the unavoidable diffusion pattern, i.e. the special concentration gradient, is bound, which is unavoidable in diffused zones.

It is also known ("Electronics" [May 18, 1962], 49 to 53) on a semiconductor output body to apply an epitaxially deposited semiconductor layer, a mesa. In this mesa the impurity concentration can be selected independently of that of the starting semiconductor body, so that in the production of zones in the mesa of the impurity concentration in the starting semiconductor body is independent. However, such a method has the disadvantage that the surface

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of the semiconductor body of the finished semiconductor component is no longer flat and that when it is applied a protective and / or masking oxide layer, these irregularities often occur at the edges of the mesa having.

It was known for the production of special, non-planar semiconductor components (»IBM Technical Disclosure Bulletin «, 3 [1961], 8, 29) in depressions of a semiconductor body from semiconductor material epitaxially deposit the vapor phase and the deposited one adjoining the depression Remove material; however, the semiconductor body produced in this way remains uneven.

It was also known (United States patent 3 000768) for the production of a semiconductor component, in the case of the PN junctions from both sides of a disk-shaped output semiconductor body are generated after the production of the first (emitter-base) PN junction between the semiconductor body and maintaining a reverse voltage on the emitter electrode to apply to the emitter-base junction to produce the bordering embellishment layer of a precisely defined thickness and then electrolytically to etch a recess in the semiconductor body in order to then epitaxially in this recess Precipitation of semiconductor material in the KoI lector zone to attach.

In contrast, the invention is based on the object of a method for producing a semiconductor component to create of the type mentioned, in which the semiconductor body of the finished Component has a surface that is as flat as possible.

According to the invention, this object is achieved in that initially in the disk-shaped Starting semiconductor body, starting from this large surface, a recess is made, wherein at least the last phase of the production of the recess in a chemical etching treatment there is that subsequently semiconductor material which is different from that of the starting semiconductor body is grown epitaxially on the surface and in the recess and so is the recess is filled out that after that on the surface of the starting semiconductor body grown material is removed, so that a flat surface with a surface part belonging to the starting semiconductor body and one grown in the recess Part of the surface belonging to semiconductor material arises, and that finally the still missing, for the semiconductor circuit element required zones in the grown in the recess Semiconductor material are formed.

This has the advantage that the mesa is attached in, instead of on the output semiconductor body is. that is, a semiconductor body with a uniformly flat and level surface for further treatment is available.

The semiconductor junction can be a PN junction, a PP + junction, an NN + junction and / or a Be heterojunction between semiconductor materials of different chemical composition.

Layers consisting of different semiconductor materials can advantageously be used one after the other get knocked down. “Various semiconductor materials” are not just semiconductor materials to understand, which consist of different chemical elements, but also those.

which differ only in their conductivity and / or their conductivity type.

Another shallow depression can be made in the starting semiconductor body, so that when

S Removal of on the surface of the output semiconductor body deposited material the thickness of the semiconductor material to be removed can be determined, as will be explained in more detail below.

The semiconductor material deposited on the surface of the starting semiconductor body can can be removed by mechanical polishing and a subsequent cleaning etching treatment. An important further development of the process

according to the invention is characterized in that after the depression by epitaxial precipitation has been filled by semiconductor material and by removing on the surface of the starting semiconductor body A flat surface was created again with the deposited semiconductor material isi, an oxide layer is applied to this. At the one with epitaxially deposited material filled recess, an opening can be made in the oxide layer through which a

»5 impurity in the epitaxially precipitated Material can be diffused. The epitaxially deposited material can continue through Deposition of a metal layer in the opening are provided with a connection contact.

The semiconductor circuit elements formed in the semiconductor component produced according to the invention are preferably diodes and transistors.

It is advantageous to have all of the zones of the semiconductor circuit element to be formed in the recess epitaxially more depressed. Form semiconductor material, the output semiconductor body serves as a carrier body for the semiconductor circuit element.

A homogeneous output body is preferred used.

The invention is explained in more detail with reference to the drawing, in the exemplary embodiments of the method are shown according to the invention.

F i g. 1 to 4 show cross sections of phases in dor Manufacture of a semiconductor diode according to the method of the invention, and

F i g. 5 shows a fully completed transistor, which is produced using a method according to the invention.

In the drawing, hatching is omitted for the sake of clarity, and for corresponding parts The same reference symbols are used in the various figures.

A p-silicon body with a specific

Resistance of 2 Ω-cm in the form of a disk with a diameter of 2 cm is first ground to a thickness of about 400 µm and then through Etch polished to maintain a clean smooth surface with a minimum of crystal defects.

A layer of oxide is grown on the body, e.g. B. in that the body 4 hours is heated for a long time at 860 ° C in moist oxygen saturated with steam at 98 ° C. A photo-curing one Lacquer layer is applied to the oxide layer

«5 applied and exposed in such a way that a surface part with a cross section of about 50 µm ² is shielded from the incident radiation. The unexposed parts of the lacquer layer are in one

exposed lacquer layer by sintering ^ je ^ who J _material ^ _been ^ _{SQ that}

t ^ A SStes 5 with the exception of the cavities the surface dated

exposed

den Die Oxydjcjicht

(a 8 ^ *
suitable) is used in ^Κο Π * '«° f
a T.efe of 2 wji regularized
der maxima en Tderan * ^
forming deeper cavity zulasag * · Bg ^
slow-acting etchant commits from svo «jnw_
»En 49 Vt» # «hydrofluoric acid and 95 vc * um
share 70% nitric acid.
The remnant of the ^

pitric acid existing etchant can be achieved, which colors p-silicon and does not color η-silicon. _Further e color-forming etchants for obtaining one

visible difference between n- and p-Matena- ^ _& ^. ^ _{nth bek}

_f aÄbiWencle etchant to differentiate between __ _{d ufld between n} . _{and n} + materials too

fc,

serenely and. again one

layer applied that

for the purpose of EA » ¹¹ « »^^
part of the body,

? SAS '

After degreasing and boiling in 70% salt-pitric acid, a layer of oxide is again _{removed from the} layer of oxide over a part of the surface in order to make contact with the epitaxially deposited η-material, and the layer of oxide from the reverse of the body Lternt to get with the _P body _P er

^^^ SSÄiÄlr ^ S £? K ^ X \ -M ^ can thereby

usable, st. Em ^^^ S ^ J.JÄ! be made that gold with 1 weight percent

known and consists of 3 parts by volume W Mger riu β _vacuum ^ _the ^. ^ _surface .

onvassersoffsaure 3 Vo ^ mteden glacial acetic acid - _tei l, from which the oxide layer has been removed up

Volume dividingTOVoiger nitric acid. _{and then the Kö bd 400} o _C

Rieses Vcf ereitenk ^ η

^ Ä ^ g ^ n ^ ÄeSäc ^ jhHeMch des little Te ^ ^^ mpftund. with g-ph.sche art prior to the heating of the upper SI ^fl ^ then on manner on all

Seconds
the

n _PP lSe layer follows the outline of the upper

SchfS ^ KÖrneS De e ⁸ pitactic precipitation flat des ^ ^or P ^ers · »™ ^v . _{K {j dh H ch} .

SS ^ SÄÄ «from

^existing caustic ^ assüÄt ^ is ^?

Qf d is diffused in _{over part of the Κ} ο _{φεΓ5, where}

S of the ^ n-type 45 the contact is required. A layer of aluminum Ä? is then applied to the doped with phosphorus

Applied to the surface and alloyed with the body by heating. This process makes it possible, simultaneously with the precipitation of the aluminum _and the alloying, to form p-contacts with parts of the Kor-P "? Which are not doped with the phosphorus.

Te

^ t ^ S ^ SfSlÄ the other side of the body becomes egg,

ife ^ ne amount of phosphorus trichloride are formed in the p-contact thereby that the body through

small amount of ™ »* ν> _{h R fc} _ alloying on a metal strip covered with gold

^ ÄÄiL is content. The gold layer can be 1 weight per

Stactical Sna

SefSSeÄg the optiSSe'en surface that has been _removed, for example, by a layer of Saudei e ^ iSktLh ^ deposited. A metal disc covered with wax is brought into contact with the λΪ free side of the body. Cooling and when the wax has solidified, the disk is

ÄS ^ S:

mon-contact 4in dErch heat pressure connection ei: Wire to be attached. An aluminum layer can also be applied, which extends from the contact extends over the insulating oxide layer to the Kor perrand.

Fig. 1 shows the original semiconductor body Immediately after the deep cavity 2 was formed, the shallow cavity 3 and an oxide layer also wove

the body! immediately after the Au "

Bringing the epitaxial n-layer S. It is noticed

sees- that the outer surface of the layer 5 corresponds to the outline of the

ng bp surface of the body 1 follows. Polishing up to

io that broken line 6 results in a flat upper

e from the area, and in the case of dyeing are the limits of the

epi-cavities 2 and 3 are not visible. When polishing up to

would take the broken line 7 are the boundaries of the

both cavities 2 and 3 visible when staining what

aj means that the remaining depth of the cavity 2

Voiger is within the desired tolerance. Would that

r SaV polishing continued until broken line 8, so

earth, the cavity 3 would not be visible during dyeing, what

colors. means that the remaining part of the cavity 2

one would then be too flat. It is noticed that the flat

iteria- cavity 3 is not necessary, but convenient-

.a ^ nte can be attached and used for the sake of convenience. at

appeared to be repeated production of larger numbers of such

.en to devices can regulate the times of the

Actions together with an inspection are sufficient

r being together;

the F i g. 3 shows the body after polishing and

one of the application of an oxide layer 9, and

) itak- Fig. 4 shows a completely finished diode with

ι ma a metal strip 10 and an associated alloy

iirten tion zone 11, a recrystallized n-zone 12

jrper with associated contact 13 and an aluminum layer 14th

The conductivity type and the specific resistance

) cent of the original body and the eptitactic

; hen- down material can easily

.on- as required for each desired type of diode

O ⁰ C can be selected. In general, conditionally with one

ion diode the desired breakdown voltage

the specific resistance of the original body,

ld - and the specific resistance of the precipitated

one material is less,

with For the production of an npn transistor you can

tho- the same steps as described above, up to the

) ber- in F i g. 3 can be carried out. The differences are that the original

because the body has η conductivity, the depth of the deep

inner cavity is 2 µm and a slow etching

.lefe tel is used, the deposited epitaxial

. where the layer is e.g. of the p-type, with boron instead of with

is not doped with phosphorus, is 3 µm thick, has a specific

erte see resistance of only 1.5-ΙΟ " ² Ω-cm

can learn, and the body is polished to a stuffed one

I, a cavity of 1 µm depth remains,

us polishing can be controlled by

Cör- that the sheet resistance in the cavity during

iert the polishing process at intervals according to a four-point test method is measured. If the height

a position is too small for measurement to be easily possible.

to borrow, if necessary, the shift

resistance to a specially designed

xo additional cavity measured with a larger circumference

will.

.lti- The emitter electrode is thereby formed such that a the Oxydschicht9 (Fig.3) through a small upper surface part is removed and the body ak't 15 minutes is heated in a phosphorus-containing atmosphere at 1050 ⁰ C or-. This atmosphere can be obtained by passing the steam generated by heating 1 phosphorus nitride at 1000 ° C. in a nitrogen flow over the body. t4 The diffusion results in an η-layer with a high surface concentration of phosphorus and uf- with a thickness of about 0.5 μm, so that a base zone also arises with a thickness of 0.5 μm. The oxide layer 9 (FIG. 3) is removed over a surface portion which practically encloses the small surface portion, but not completely, in order to allow the passage of a conductive layer onto the oxide layer for connection to the emitter electrode.

The semiconductor body is again, exactly as in the previous example, on a covered with gold Metal strip attached, which serves as a collector connection. The gold can contain 1 percent by weight of antimony contain. Aluminum layers serving as emitter and base connections can be deposited by vapor deposition be applied.

Fig.5 shows the fully completed transistor with a diffused emitter zone 15, an aluminum layer 14 for connection to the zone 15 and an aluminum layer 16 for connection to the base zone in the cavity 2.

»O Instead of attaching the emitter zone by diffusion For example, the emitter electrode can be formed by alloying or by epitaxial deposition. Alloying can be carried out by depositing the material to be alloyed on the small part of the surface

»5 and subsequent heating take place. In the case of epitaxial precipitation, the material already deposited in the cavity can be etched away to the required material thickness on the walls of the large cavity, and n ⁺ material can be epitaxially deposited to refill the cavity and then polished. It is noted that the emitter electrode can usually only be formed by the epitaxial deposit if this measure can be carried out at a temperature sufficiently low to prevent excessive diffusion of impurities.

In practice, multiple diodes or transistors can be formed on a single body the semiconductor body being subdivided as the last manufacturing phase in order to achieve individual components can be. Furthermore, several bodies can be attached to a common metal support and be polished at the same time.

In certain cases, for example in the manufacture of switching transistors, it may be desirable to deposit a two-part zone in a cavity formed in an original semiconductor body. So z. B. in a cavity in a p-output body with a specific resistance of I Ω · cm first a more heavily doped η zone with a thickness of 5 \\ m and with a specific resistance of 0.01 Ω-cm and then a weaker one doped η-zone with a specific resistance of 0.5Ω · αη deposited in order to serve together as a collector zone, the p-body only being effective as a carrier. The base and emitter regions are then applied by any suitable method. The more heavily doped zone makes a low collector series resistance possible, and the collector connection contact can be applied on the same side of the semiconductor body as the emitter and base connection contact.

The method which is based on the FIG. I and 4 described manufacture of a diode refers, can be used to attach an isolated zone for the production of a structure of half

409 649/34:

Conductor circuit elements with a common semiconductor body up to that shown in FIG. 3 Apply phase. Further switching elements can be in the output body at the same time or at a different point in time 11 can be attached.

The method of the invention is generally applicable to the manufacture of an assembly of semiconductor circuit elements with a common semiconductor body advantageous in which one or more semiconductor diodes and / or transistors and / or other switching elements, such as resistors and capacitors, in a common semiconductor » body to be attached. The other circuit elements can also be formed by the formation of cavities, in which semiconductor material is deposited epitaxially, are produced.

Using the method according to the invention

10

It is possible to use a crystal with a plane Form surface zones zn, the dimensions of which can be precisely controlled and which are practical equally doped and furthermore can be doped more weakly than the starting semiconductor body. This in In contrast to normal planar technology, which uses diffusion techniques in which the redoping of already existing concentrations of impurities Zones with inhomogeneous

ίο concentrations of impurities and therefore inhomogeneous specific resistance with eiricin.

The method according to the invention readily enables the manufacture of an extensive Series of circuit elements, such as crystal diodes,

is transistors, circuit elements with four layers and forming semiconductor circuit elements with a common semiconductor body.

1 sheet of drawings

Claims (11)

Patent claims: 1. A method for producing a semiconductor component with a semiconductor body, in which at least one semiconductor circuit element is formed with at least two zones with different conduction properties, in which semiconductor material is grown epitaxially from the vapor phase ta on one of the large surfaces of an output semiconductor body and the zones required for the semiconductor circuit element in the grown semiconductor material are formed, characterized in that first in the disk-shaped output semiconductor body, starting from this large surface, a recess is made, with at least the last phase of the Her position of the recess in a chemical etching treatment, that then semiconductor so material , which is different from that of the starting semiconductor body, epitaxially grown on the surface and in the recess and so the recess is filled, that after that on the surface dc ^ Starting semiconductor body as per grown material is removed, so that a flat surface is created with a surface part belonging to the output semiconductor body and a surface part belonging to the semiconductor material grown in the recess, and that finally the missing zones in the in the recess grown semiconductor material are formed. 2. The method according to claims, characterized in that that the epitaxial semiconductor material successively as layers of different Semiconductor materials is grown. 3. The method according to claim 1 or 2, characterized in that in the starting semiconductor body Another shallow indentation is made to help when removing on the surface d? s Starting semiconductor body grown material the thickness of the semiconductor material layer to be removed to determine. 4. The method according to any one of claims 1 to 3, characterized in that the on the surface of the starting semiconductor body grown material removed by mechanical polishing will. 5. The method according to any one of claims 1 to 4, characterized in that after the Recess has been filled by epitaxial growth of semiconductor material and through Removing semiconductor material grown on the surface of the starting semiconductor body Again a flat surface has been created, on which an oxide layer is applied. 6. The method according to claim 5, characterized in that that over the filled with epitaxially grown material recess a Opening is made in the oxide layer. 7. The method according to claim 6, characterized in that through the opening a doping material is diffused into the epitaxially grown material. 8. The method according to claim 6 or 7, characterized in that the wake-up epitaxially. sene material by nledwwbtawn of a metal layer is provided with a connection contact in the opening of the oxide layer. 9 The method according to any one of the preceding claims, characterized in that a Semiconductor circuit element in the form of a diode is formed. , 10. The method according to any one of claims 1 to 8, characterized in that a semiconductor circuit element in the form of a transistor . is formed. * ^v 11. Method according to one of the preceding Claims, characterized in that all zones of the semiconductor circuit element to be formed are formed in the semiconductor material epitaxially grown in the recess, the starting semiconductor body only serves as a carrier body for the semiconductor circuit element.