DE2824027A1 - Semiconductor component contacting system - has strip shaped, proud terminal contact with cross=sectional restricted bending section - Google Patents

Abstract

The contacting system enables extremely low ohmic connection of a lowest possible lead inductivity a capacity. It is partic. suitable for high frequency components for millimetre wave range. The metal terminal contact (4) stands proud of the semiconductor body. It has a bending section (5) whose cross section is reduced as compared with the other contact parts, while forming an integral portion of the semiconductor component (1). The bending section pref. connects directly to the contact part (6) connected to the semiconductor subst rate. When the component is a high frequency Schottky diode the contact part (6) forms a small area and rectifying metal-Schottky contact. The metal contact terminal may be deposited on and partly dissolved from the component surface.

Description

The invention relates to a semiconductor component according to the

Generic term of claim 1. The object of the invention is based on specifying a contacting system for a semiconductor component with which this extremely low resistance and with the smallest possible lead inductance and capacity can be connected. Such a contacting system is especially required for ultra-high frequency semiconductor components, for example should be used in the mm wave range. This is for example to mixer Schottky diodes, which operate at an assumed frequency of fO = 1600 GHz and a series resistance of R5 = 10 Ω a junction capacitance of only CO = 10 14 F.

So far, attempts have been made to obtain the values given above for Schottky diodes to achieve with components where the Schottky barrier area in diameter is not greater than 1 - 2 Am and this Schottky contact with a whisker connection is provided. Whisker diodes of this type, however, have the disadvantage that the electrical Contacting must take place through the pressed whisker and therefore the reproducibility the electrical values cause difficulties and the reliability of the component is decreased. Also the adjustment of the whisker contact to the metal Schottky contact requires considerable technical effort and complicates the Integration of the Schottky diode in an integrated semiconductor circuit.

As an alternative to the Whisker-Schot # tky-Diode, a conventional Beam-Lead-Di #: 4e could be considered, which is mechanically more stable, but a product which is smaller by a factor of 2 - 3 than that of a Schottky whisker diode. This is based on the fastening technology used in beam-lead components, since the lead strips cause parasitic capacitances, which are mostly greater than the actual diode capacitance.

The invention is therefore based on the object of a new one for ultra-high frequency components indicate suitable contact establishment. Furthermore, advantageous procedures for the production of these semiconductor components can be found.

This object is achieved by the characterizing features of the patent claim 1 solved.

In the semiconductor component according to the invention, that is from the semiconductor body protruding metallic connection contact is an integral part of the semiconductor component, preferably by deposition processes and at least partial redeposition is made from the surface of the semiconductor device and is movable.

Through this connection strip firmly connected to the semiconductor body there is no difficulty in making contact, like this with the whiskers was the case, which had to be additionally formed. The ezz-in accordance with Terminal strip has a bending point, which is preferably directly to the with connected to the semiconductor material connected part of the terminal contact. The contact area on the active zone of the semiconductor component can be kept extremely small and is protected from excessive loads by the existing bending point. The parasitic occurring between the connection strip and the substrate Capacity is kept extremely small by the distance from the semiconductor surface. There is also the possibility that the metal contact on the active zone of the Semiconductor component, for example the metal Schottky contact, near the edge of the semiconductor body is arranged on a mesa-shaped semiconductor layer. The remaining surfaces of the semiconductor body can be used to implement a Schottky diode largely with a large area that makes ohmic contact with the semiconductor body Terminal contact are provided, which thus also an attachment of the half-body on a carrier body, in which the barrier layer is perpendicular to the surface of the carrier body runs.

There is also the possibility that the movable terminal strip connects two semiconductor bodies together by separating a unified Semiconductor body have arisen. In this case, for example, the one semiconductor body wear the metal Schottky contact, while the other semiconductor body forms only a low-resistance connection body, whose (iM ctrical dimensions largely correspond to those of the Schottky e. These two semiconductor bodies can dt, n in a common microwave housing are arranged, the two semiconductor bodies either on opposite support bodies or on a common one Carrier body can be attached. The metal connector strip does not have to be have the shape of a band of uniform cross-section, but he can also for example, have the shape of an outwardly widening wedge.

For the production of the component according to the invention are different Process methods are particularly suitable, the content of which is essential to the invention in particular from claims 10, 11, 12 and 17 results. The details these method methods are to be used in the following on the basis of the exemplary embodiments shown are described in more detail.

Figures 1 and 2 show in section and in a perspective View of the basic structure of a Schottky ultra-high frequency diode, which is connected to a Is provided supply line system according to the invention. A semiconductor body 1 is made for example from a heavily doped + -conducting semiconductor base body 2, the on one surface side with a mesa-shaped active zone 3a is provided. This mesa-shaped area can be angular; however, he will prefer in order to avoid high fields and thus the effects of noise, without edges, in particular circular be. The active zone 3a is connected to a connection contact 6, for example a barrier layer 7 is generated opposite the active zone 3a of the semiconductor component. This connection contact 6 merges seamlessly into the movable connection strip a, which in the immediate vicinity of the terminal contact 6 has a bending point 5 with reduced Has cross section. With the help of this bending point, the connection can be touched 4 stand out from the semiconductor surface in such a way that it has the desired contact assumes a suitable protruding position. The exposed areas of the n + -conductor Base body 2 are preferably provided with an ohmic connection contact 8, which also covers the side surfaces of the semiconductor body and thus the semiconductor component encloses almost on all sides. This connection contact 8 enables the semiconductor body 1 with its surface side opposite the active zone 3a on a carrier body can be attached. But there is also the possibility that the semiconductor body connected with its narrow side adjacent to the active zone 3a to a carrier body is, so that the barrier layer 7 is perpendicular to this support body and the Metal connection strip 4 with a further contact strip on the carrier body can be connected. This type of contact is referred to in the literature as a notch-front structure described.

In the Schottky semiconductor component according to FIGS. 1 and 2, the active area 3 ##, for example, has a diameter of 1-2 μm. The semiconductor body can for example consist of GaAs or silicon, with a GaAs semiconductor body the Schottky barrier layer, for example with the help of an aluminum layer and at a silicon body is realized with the help of a platinum silicide layer. The immediate Terminal contact 6 located above the active area 3a is generally one multilayer, for example a 3-layer, structure, during the Terminal strip 4 is at least 2 layers, with only at the bending point 5 a metal layer may be present.

An advantageous method for manufacturing a semiconductor device according to FIG. 2 is described below with reference to FIGS. 3-7. Show it the figures partly in section, partly in a plan view only that edge area of the Semiconductor body, the active semiconductor area and the associated terminal strip having.

The semiconductor body according to FIG. 3 in turn consists of one heavily doped base body 2 on which a thin layer 3 of lightly doped Semiconductor material is arranged. The n + -doped layer 3 can be an epitaxial layer or around one by ion implantation generated Act a layer that is, for example, about 0.2 Rm thick. On lvi n-doped layer there is a double make up of the insulating layers 9 and 10. For example the lower layer 9 is an SiO2 layer and the one on top Layer 10 around a silicon nitride layer.

This double mask is masked with a photoresist layer 11, the leaves a window over the area of the semiconductor surface where the Schottky barrier layer should be generated. The semiconductor body is then passed through the layers 9 and 10 an opening 12 etched, e.g. B.

wet-chemically, dry-chemically or by ion etching, up to the weakly doped n-layer 3 is enough. The metal layer 6a, which is for example at a GaAs base body made of aluminum or Pt-Ti-Au, forms with the n-doped Layer 3 is a barrier layer 7 and also acts as layer 13 the photoresist 11 down.

From there it is removed again together with the photoresist.

A double masking layer was chosen, especially the negative ones Avoid the effects of nin-holes.

According to FIGS. 4a and 4b, after the production of the Schottky contact forming metal layer 6a a strip-shaped part of the upper and for example Mask layer 11 consisting of silicon nitride is removed.

The semiconductor surface is then covered with another layer of photoresist 14 covered, but the metal contact 6a and the strip-shaped uncover the area of the lower masking layer 9, the b; is for example from Silicon dioxide is made free. The surface structure is shown in the top view from Figure 4b.

Then according to the figure 5a and the associated top view in Figure 5b, a further metal layer 6b or 4a vapor-deposited, which consists, for example, of gold-nickel and has a thickness of 2000 - 3000. This metal layer covered both the rectifying contact 6a and after the removal of the photoresist layer 14 a strip-shaped, towards the edge of the semiconductor arrangement part of the exposed lower mask layer 9 extending towards it. A narrow area 15 of this metal contact strip on the semiconductor device is now in immediate Proximity to the contact 6a or the partial layer 6b arranged thereon with a further photoresist layer 15 covered. As a result, the later bending point of the Connection strip defined. The metal strip is then according to d # r Figure 6a and the associated top view 6b, preferably galvanically reinforced.

On the contacts 6a and 6b on the active area of the semiconductor component a layer 6c thus grows on the other parts of the metal strip is denoted by 4b. The lacquer layer 15 prevents reinforcement at the bending point of the metal strip 4a. In which electrodeposited material it is, for example, gold in a thickness of 1 - 10 µm. The semiconductor surface is then covered with another mask, not shown, which the active Covered area of the semiconductor component and the metal connection strips. In the remaining areas of the semiconductor surface are the mask layers 9 and 10 and the active semiconductor layer 3 removed. The exposed part of the n -doped Base body 2 can then be provided with an ohmic contact 8, which the Surrounds the component on all sides. Before doing this step, however, there is also the possibility of the semiconductor body by a further etching step in his To reduce the dimensions in order to achieve in this way that the connection strip 4 protrudes over the edge of the semiconductor body.

Finally, the one located under the metal connection strip 4 is also used Mask layer 9 is selectively removed, and preferably also the underlying Material of the active semiconductor zone 3 removed, so that only the one under the Schottky contact 6a lying active semiconductor region 3a is retained. Through these etching steps the metal connection strip 4 including its bending point 5 is removed from the base separated and can therefore be lifted. To raise or bend the connection strip For example, a ground vacuum capillary can advantageously be used.

Another manufacturing method results from FIGS. 8-11 for a semiconductor component with a bendable and integral lead strip. According to FIG. 8a and the associated top view from FIG. 8b, the surface the semiconductor arrangement in turn initially covered with a double mask 17 and 18, the lower mask layer being made of silicon dioxide, for example, and the upper mask layer 18 consists for example of silicon nitride. Then with the help of the usual Photoresist, masking and etching processes the double mask 17 and 18 and the n-doped active semiconductor layer 3 except for a strip-shaped area that extends to the Edge of the semiconductor arrangement extends out, removed. The exposed part of the n + -conducting carrier body 2 can in turn with an ohmic metal connection contact on all sides 8 are provided.

Thereafter, according to FIG. 9a and the associated top view in FIG 9b into the double mask layer 17 and 18 with the aid of the mask and etching technique Introduced opening, in the manner already described, a metal contact 6a is produced, which makes a rectifying contact with the conductive layer 3 forms.

The semiconductor surface is then covered with a photoresist layer 16 covered that also in the strip-shaped part form small islands 19 can in order to use these openings in the metal layer to be produced later to facilitate the undercutting of this metal layer.

According to the figure 10 is then on the exposed part of the upper Mask layer 18 a first metal layer 4a applied over the contact layer 6a is denoted by 6b. This layer 4a is in turn in the area of the bending point covered with a narrow photoresist strip 15 and then galvanically reinforced, so that the metallic connecting strip 4 in the areas 4b and 6c its final Layer thickness gets.

Finally, according to FIG. 11, the silicon dioxide, for example, is selectively made existing layer 18 removed under the metal contact strip 4, so that the connecting strip can be lifted in the direction of the arrow. The bending point 5 ensures that the strip has sufficient elasticity. That way you get a structure in which the active region of the semiconductor device is provided with a mask layer 17 remains passivated, which consists for example of silicon nitride.

Of course, there is also the possibility of this silicon nitride layer still to be removed and a mesa etching to be carried out, as shown in FIG. 7 has been described.

If a so-called Sub-i1m adjustment option is available, z. B. an i.] Electron beam exposure system, an arrangement according to 1 and 2 can also be produced in a far simpler manner. It will then according to FIG. 12a and the associated top view in FIG. 12b of the active one Semiconductor layer 3 applied a small-area Schottky metal contact 6a. Thereafter can, for example, in a strip-shaped manner with the help of the very precise mask technology Area on the semiconductor body, a partial oxide layer 9, for example from Silicon dioxide. The connection strip is then with the help of the already described methods applied to this passivation layer 9, the is later removed again by selective etching under the metal strip. Will in addition, a mesa etching of the weakly doped active semiconductor layer 3 was carried out, in this way a structure according to FIG. 1 is obtained.

FIG. 13 shows a contacting method for a semiconductor component according to the figure 1 according to the principle of so-called notch-front contact. A Carrier body 30 made of insulating material has two closely adjacent interconnects 19 and 20 on. The semiconductor body 2 is on one of these interconnects with its Put on the narrow side and connected via the ohmic connection contact 8.

The lead strip 4 is angled so that it is with the other connection interconnect 19 comes into contact and soldered or verschz with this can be.

FIG. 14 shows how a semiconductor diode according to FIG Figure 1 can be installed in a microwave housing. This microwave enclosure has two connection plates 22 and 23, which are separated by an insulating ring 24 from one another are spaced. In the housing 21 is the semiconductor body 2, which with his Ohmic connection contact 8 is connected to the carrier plate 22, for example. The connection ribbon 9 is angled so that it connects to the upper connection plate comes in connection and can be attached to this.

Another structure is explained in more detail with reference to FIGS. 15 and 16. An elongated, highly doped semiconductor body carries at one end the Schottky diode formed from the active layer 3a and the Konatkt 6, while at the other end of the connecting strip 4 going out from the Schottky diode on the low-resistance Substrate is ohmically connected (25). This spaced from the semiconductor body Terminal strip 4 has two bending points 5a and 5b, one of which is the Schottky contact and are adjacent to the ohmic contact to others.

The middle part 28 of the semiconductor body is formed in an etching or sawing step removed, so that two semiconductor bodies 27 and 26 arise, which only over the connection strip 4th are connected to each other. The low-resistance part 26 forms a connector body However, in its geometric dimensions the., 1 of the Schottky component 27 corresponds. In this way, the two semiconductor bodies are obtained when the two semiconductor bodies are installed in a microwave housing according to FIG. 16, a particularly favorable characteristic impedance adaptation for both connection electrodes.

According to FIG. 16, for example, there is a suitable coaxial housing 21, in turn, consists of two connection plates 22 and 23, which are secured by an insulating ring 24 are isolated from each other. Each one of the two semiconductor bodies is with his Ohmic connection contact 8 attached to one of the connection plates 22 and 23 in such a way that that the two semiconductor bodies 26 and 27 are directly opposite one another.

Inside the housing, the two semiconductor blocks are through the flexible connection strips 4 ohmically connected to one another. It is, of course also the possibility of the two semiconductor bodies in a notch-front manner on two to fasten adjacent interconnects on a common carrier body.

In the manufacture of a semiconductor arrangement according to FIG. 1 or 11, it must also be noted that these components are of the planar construction are produced from a semiconductor wafer, which has a large number of such Components contains. D # LIt is the utilization of the available semiconductor oil) area and appropriate later separation of these components can be achieved that the Connection strips produced according to the invention over the respective edge of the individual component protrude. In this way, sufficiently long connection strips can be produced, which also makes contact using notch-front technology on a flat support body enable.

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Claims (20)

Claims 9 semiconductor component with at least one of the semiconductor body protruding metallic connection contact, characterized in that the strip or strip-shaped connection contact (4) one in cross-section opposite the other Parts (4, 6) of the protruding contact has reduced bending point (5) and is an integral part of the semiconductor component (1). 2) Semiconductor component according to claim 1, that the bending point (5) is immediate on the part (6) of the connection contact connected to the semiconductor material (3a) connects. 3) semiconductor component according to claim 1 or 2, characterized in that that it is a high frequency Schottky diode and the metallic connection contact (6) the connection to the small-area and rectifying metal Schottky contact forms. 4) Semiconductor component according to one of the preceding claims, characterized characterized in that the metallic connection contact protruding from the semiconductor body (4) a deposition process and at least partial redeposition of the surface of the semiconductor component made movable connection strips is. 5) semiconductor component according to claim 3, characterized in that the metal Schottky contact (6a) near the edge of the semiconductor body on one over the limited semiconductor layer (3a) protruding from the semiconductor surface is arranged, while the remaining surfaces of the semiconductor body - including the side surfaces - Largely with a large area that makes ohmic contact with the semiconductor base body Connection contact (8) are provided, which also attaches the semiconductor body on a carrier body, in which the barrier layer (7) perpendicular to the surface of the carrier body runs. 6) Semiconductor component according to one of the preceding claims, characterized characterized in that the movable connection strip (4) has two semiconductor bodies (26, 27) connects to each other by dividing a unitary semiconductor body have arisen. 7) semiconductor component according to claim 6, characterized in that the one semiconductor body (27) carries the metal Schottky contact (6), during the other semiconductor body (26) a low-resistance connection body with largely the same geometric dimensions is. 8) semiconductor component according to claim 7, characterized in that the two semiconductor bodies (26, 27) each other in a common housing (21) opposite on one or two support bodies (22, 23) with their large-area Connection contact (8) are ohmically attached. 9) Semiconductor component according to one of the preceding claims, characterized characterized in that the metal strip (4) has the shape of an outwardly widening Wedge has. 10) Method of manufacturing a semiconductor device according to a of the preceding claims, characterized in that on the semiconductor surface a first mask (9, 10) is applied over the for an ohmic or rectifying contact to a semiconductor zone (3) provided surface area has an opening (12) into which a first metal layer (6a) is introduced, that then the semiconductor surface with the exception of the first metal layer (5a) and an adjoining strip-shaped area with a Cover mask (14) is covered that then on the surface a second metal layer is applied, which is partially removed with the cover mask (14) that then a narrow area of the remaining strip-shaped metal layer (4a) following the first metal layer to define the bending point (5) with another mask (15) covered and the exposed part of the metal strip is further reinforced (6c, 4b), and that finally the one between the metal strip and the mask layer (9) lying on the semiconductor body is removed and the metal strip (4) is raised. 11) Method according to claim 10, characterized in that the first Mask (9, 10) has two layers and the top layer (10) over the surface area for the metal strip (4) is removed before its application that after reinforcement of the metal strip this is covered and in the remaining areas the surface the semiconductor body is exposed and, if necessary, also removed, and that finally the lower layer (9) remaining under the metal strip the first mask is removed by selective etching, so that that with the first Metal layer (6a) connected metal strips (4) can be raised. 12) Method for producing a semiconductor component according to claim 10, characterized in that only one strip former provided for the metal layers Part of the semiconductor surface is provided with the first mask layer (17, 18), the remaining areas of the semiconductor body, optionally after removal of a Surface zone with an ohmic metal connection contact (8), that an opening is then made in the first mask layer, in which on the semiconductor surface a metal layer (6a) is applied that then the Semiconductor surface with the exception of this metal layer and the first mask a cover mask (16) is covered and a further metal layer is applied, which is partially removed again with the cover layer, that afterwards a narrow one Area (15) of the remaining metal strip (4) on the first mask for definition the bending point (5) is covered and the exposed part of the metal strip is reinforced becomes 4b, 6c), and that finally at least part of the first mask under the Remove the metal strip and lift the metal strip (4). 13) Method according to claim 12, characterized in that the first Mask layer is two-layer and selective after the production of the metal strip only the top layer (18) is removed, so that the lead surface in this Area with the lower layer (17) remains passivated. 14) Method according to claim 11, characterized in that the lower Layer of the two-layer first mask made of SiO2 and the upper layer made of Si 3N4 consists. 15) Method according to claim 13, characterized in that the lower The layer of the two-layer mask consists of Si 3N4 and the upper layer consists of SiO2. 16) Method according to claim 12 or 13, characterized in that Finally, the lower layer of the two-layer first mask is also removed and the surface zone is selectively removed. 17) Method of manufacturing a semiconductor device according to a of claims 1 - 9, characterized in that a small area of the semiconductor surface is covered with a first metal layer (6a) that then on the semiconductor surface a masking layer in a strip-shaped region adjoining the first metal layer (9) is applied that thereafter the semiconductor surface with the exception of the first Metal layer and the strip-shaped area is covered with a masking mask and a second metal layer is applied to the surface, which together with the mask is partially removed again, while the remaining Metal strips on the masking layer in a narrow area with another Cover mask covered becomes that afterwards the exposed ~ areas of the metal strip are further reinforced and the masking layer is formed under the metal strip is selectively removed and the metal strip is lifted. 18) Method according to claim 17, characterized in that the masking layer consists of silicon dioxide. 19) Method according to one of the preceding claims, characterized in that that the metal strip with a vacuum capillary in one for the component contact suitable location is brought. 20) Method according to one of the preceding claims, characterized in that that the metal strip is galvanically reinforced.