DE2218928B2 - Semiconductor arrangement with at least one electroluminescent PN junction - Google Patents

Description

The invention relates to a semiconductor arrangement with at least one electroluminescent PN junction according to the preamble of claim 1.

A semiconductor device of this type is known from BE-PS 7 53 886

In such arrangements, the light wave emitted by an electroluminescent PN junction is often synchronized with an excitation current modulates an information-carrying signal One possible application is, for example, remote measurement. In this case, the electroluminescent semiconductor device in the vicinity of the focal point of a optical system arranged to a beam of light that is emitted in the direction of a target. The one from the target to that Transmitter reflected light beam is focused on a photodiode, whereby the distance between transmitter / receiver and target is due to the transit time between the sending side and the receiving side is determined.

The lack of temporal homogeneity of the emitted from different parts of the arrangement With a large PN transition, light can result in an error of more than 0.20 m with a measured Express a distance of 1000 m.

The present invention has for its object to provide a semiconductor device according to Design the preamble of claim 1 so that even with a large area of the emitting PN transition is the time delay between that of the edge zone and that of the middle zone emitted light is minimal.

The aforesaid object is achieved according to the invention the features specified in the characterizing part of claim t solved.

Further refinements of the invention result from the subclaims

Through the contacting strip or strips extending to the center of the ring, the Amount of time delay between those emitted by the edge and center parts of the PN junction Reduced light radiation With such an arrangement, the time delay and, accordingly, the error resulting from a remote measurement can be reduced by up to a factor of 10 to 15. The size of the time delay is the smaller, the is .'smaller the uncovered emitting surface For telemetry purposes, however, a minimum of available surface area cannot be fallen below for reasons of intensity.

Two embodiments of the invention are shown in the drawing and will be described in more detail below described. It shows

1 shows a plan view of a first embodiment of a semiconductor arrangement with an electroluminescent PN junction, F i g. 2 shows a section along the line I-I according to FIG. 1,

F i g. 3a to 3g the most important manufacturing stages of the electroluminescent arrangement according to FIG. 1,

4 shows a plan view of a second embodiment of a semiconductor arrangement with an electroluminescent junction and

F i g. 5 shows a section along the line H-II according to FIG. 4th The arrangement according to FIG. 1 and 2 consists of one Semiconductor substrate 10 in which a zone 11 is formed

of a PN junction is diffused in. The outline of the

Zone 11 is circular and in Fig. 1 with a

dashed line Ua indicated the surface of the

Substrate 10 and part of the zone 11 are with a Layer of a dielectric, translucent Material 12 but pulled (see Fig. 21 Electrical Contacts are on zone 11 in openings of the

dielectric layer 12 attached these contacts consist on the one hand of a ring 13 on the circumference of the zone 11 is attached within the boundary line 11a and on the other hand from four contact strips 14,15,16, and

♦ 5 17 extending from ring 13 to the center of zone 11 extend and at mutual angular distances

are arranged, which are practically equal to γ.

A conductive impermeable layer 18, represented in the figures thus by snow-like surfaces, covers part of the zone 11 and extends extends far beyond the boundary line Ha to the outside. Pie conductive layer 18 is insulated from zone 11 by dielectric layer 12 the contact points 13, 14, 15, 16 and 17, of which parts 14a, 15a, 16a and 17a protrude inward.

The conductive layer 18 forms a shield

against the light emanating from those below this layer

lying parts of the transition and in particular of

is emitted in the peripheral parts of this transition. That

Light is therefore only emitted through the window 19

The conductive surface areas 20 and 21 are used to attach wires by heat-pressure methods.

A structure of the in FIG. 1 shown type can be get the following way.

On the surface of a substrate 10 (crystal or

epitatoic layer) is a first layer 12 »(from 0.1 to 0.5 μm) of a dielectric material piedifrgescWagen (see Fig, 3n) r The substrate consists, for example, of gallium arsenide, while the dielectric material silicon dioxide ° the silicon nitride Preferably, dichimnitride is used because it has the most favorable properties in terms of masking during diffusion. Such a layer of silicon nitride is deposited on the substrate 10 by known techniques; 7, B, the substrate is exposed to a ίο mixture of vapors of ammonia and silane (SIiH ₄ ), diluted in hydrogen, at a temperature between 700 and 900 * C

Then a window 30 is made in the layer 12,? attached using a photo-sensitive varnish as masking and the nicbtmaskiei-te SQicj.üm | - nitride using a well-thinned orthophosphoric acid solution is removed (see Fig. 3b).

The next step (see Fig.3c) is the Diffusion of an impurity by one of the usual diffusion processes; the zone 11 with the elekuöiiimineszierenden PN junction formed at an N-conductive substrate 10 is the d'ifundlierte P-conductive zone 11 advantageously through the diffusion of zinc educated

After the formation of the zone 11, a second layer 126 of silicon nitride is deposited (see FIG. 3d). This layer 126 (with a thickness of 0.1 to 0.5 µm equal to that of layer \ 2a) directly covers the surface of zone 11 and represents an increase in the thickness of the dielectric material on the remainder of the substrate surface.

Openings are then made in the layer 12fr for contacting the zone 11

A conductive coating 18 is then applied, e.g. B. by evaporation in a vacuum, deposited (see Fig.3f). This coating 18 with a thickness of 1 to 3 µm is mostly made of aluminum.

Finally, by photoetching the exercise bag 18, the window through which the light is exposed emitted wii d (see Fig. 3g).

In a known manner, from the rear surface of the semiconductor substrate opposite the surface in which the transition is made, the part contaminated with zinc during diffusion is removed. A conductive layer, e.g. made of tin, is deposited on the exposed surface or gold-germanium to obtain the second electrical contact terminal of the arrangement.

In order to achieve an accuracy of the order of magnitude of centimeters at a distance of 1000 m for a remote measurement, the outer diameter of the zone 11 is chosen to be 165 to 185 μm and that of the window 19 to 50 to 70 μm. Furthermore, the ring forming the contact 13 has a mean diameter of 150 μm and a width of 15 to 20 μm, and the contact strips 14, 15, 16 and 17 have a width of 7 to 13 μm; the strips 14,15,16 and 17 protrude about 10 to 15 to radially into the window U9.

With the second embodiment of an electroluminescent Arrangement according to FIG. 4 and FIG. 5 can be the emitting surface compared to the first Embodiment according to FIGS.? -3 enlarged will.

Features of the two embodiments that correspond to one another have the same reference symbols.

In addition to the contact ring 13 and the contact _{strips 14, 15, 16 and 17, two intermediate rings 44 and 4S 1} which are concentric to the ring 13 are provided7 The rings 44 and 45 cross the strips 14, 15, 16 and 17 in their circular course.

The dimensions are, for example, for the outer diameter of zone 11 between 450 and 490 μm, for the inner diameter of the conductive impermeable coating layer 18, which limits the remaining effective part of the transition, between 310 and 350 μm, for the mean diameter of the rings 13, 44 and 45 the same 420,200 or 90 μm, for the width of the ring 13 between 40 and 50 μm, for the width of the rings 44 and 45 between 15 and 25 μm and for the width of the contact strips 14, 15, 16 and 17 between 7 and 35 μm. The contact strips 14-17 end at a distance of 20 to 30 μm from the center of the hinge.

For this purpose 3 sheets of drawings

Claims (1)

Claims; 1, semiconductor device with at least one electroluminescent PN * junction, with each Transition through in each case one into a planar delimitation area of a semiconductor substrate from first conductivity type diffused zone, is formed by the second conductivity type and wherein each zone is provided with a metallization layer which m shape the zone along its circumference The ring contacts and moves towards the center of the ring on one of the surface of the Zone partially covering layer of a translucent dielectric material extends, characterized in that the annular contact (13) in at least one, for Center of the ring extending, the zone-contacting strip continues Z A semiconductor device according to claim 1, characterized in that the annular contact (13) in mer, extending to the center of the ring contact strips (14, 15, 16, 17) continues the respect to the center in a mutual Angular distance of γ lie. 3. Semiconductor arrangement according to claim 2, characterized in that the four radial contact strips (14, 15, 16, 17) with each other by means at least one further contact strip (44,45), which is in the form of a ring concentrically within the annular ^ contact (13) is arranged, are connected