KR100272275B1 - Compound semiconductor device and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A compound semiconductor chip and its manufacturing method are provided to stabilize wavelength of the laser diode active layer by regulating heat quantity(ambient temperature) depending on the current at resistors. CONSTITUTION: A 1N type InP layer(1), an undoped InGaAsP active layer(2) and a 1P type InP layer are grown epitaxially on an N type InP substrate. The P type InP layer, the undoped InGaAsP active layer(2) and the 1N type InP layer(1) are etched in a mesa structure. A 2P type InP layer(3B), a 2N type InP layer and a 3P type InP layer(3C) are grown epitaxially as induction layers successively at the mesa-etched region. A P type InGaAs contact layer is grown epitaxially on the 3P type InP layer(3C). A mask pattern of oxide layer is prepared on the contact layer to define the electrode type and the resistor region. The exposed contact layer and the 3P type induction layer(3C) are etched in a mesa structure. The induction layers(1,3B,3C) outside the resistor region is etched to form a trench(7).

Description

Compound Semiconductor Device and Manufacturing Method Thereof

TECHNICAL FIELD The present invention relates to a compound semiconductor and a method for manufacturing the same, and more particularly, to a compound semiconductor capable of stabilizing a wavelength of a laser diode active layer and a method for producing the same.

In general, in constructing a high-speed data transmission system, wavelength division multiplexing (WDM: wavelenth division multiplexing), that is, a single mode oscillation capable of sequentially selecting and loading multiple wavelengths on one transmission line is essential. .

In the WDM mode compound semiconductor, as shown in FIG. 1, laser diodes L1, L2, ... having various wavelengths are arranged on a single compound wafer at regular intervals. At this time, integrating laser diodes having various wavelengths on one wafer is to reduce manufacturing air in a single module process. Here, the wavelength of the laser diode is changed by the ambient temperature and the amount of current injected into the active layer of the laser diode.

Thus, since a plurality of laser diodes having different wavelengths are formed for each part, wavelength selection is easy, and a plurality of selected wavelengths can be loaded on one transmission line, thereby being used as an ultra-high speed optical communication device.

However, in the laser diode according to the prior art described above, the wavelength of the laser diode active layer changes as the ambient temperature or the amount of current injected into the active layer changes from time to time.

For this reason, there is a problem that it is difficult to accurately control the oscillation wavelength of the laser diode.

Accordingly, it is an object of the present invention to provide a compound semiconductor capable of stabilizing an oscillation wavelength by controlling the ambient temperature and the amount of injection current of a laser diode.

Another object of the present invention is to provide a method for producing the compound semiconductor.

1 is a cross-sectional view of a compound semiconductor device according to the prior art.

2 (a) to 2 (e) is a perspective view for each step for explaining the compound semiconductor device according to the present invention.

* Explanation of symbols for main parts of the drawings

1,3A, 3B, 3C, 4 Current layer 2: Active layer

5: contact layer 6A, 6B: mask pattern

7: trench LD: laser diode

R: resistance

In order to achieve the above object of the present invention, according to one aspect of the present invention, a laser diode composed of a multi-layered compound layer, the active layer having a predetermined wavelength in the center of the compound layer, and the same spacing on both sides of the laser diode And a pair of heat generating means spaced apart from each other and arranged to provide predetermined heat to the active layer of the laser diode to stabilize the wavelength.

Here, the heat generating means is resistance.

In addition, according to another aspect of the invention, the step of sequentially growing a first InP layer of the first conductivity type, the active layer and the first InP layer of the second conductivity type on the compound substrate; Etching the second InP layer of the second conductivity type, the active layer, and the first InP layer of the first conductivity type to a predetermined depth to form a mesa structure; Sequentially growing a second InP layer of a second conductivity type and a second InP layer of a first conductivity type in both spaces of the mesa-type structure; Forming a third InP layer of a second conductivity type on top of the mesa structure and the InP layer of the first conductivity type; Forming a contact layer on the second conductivity type third InP layer; And etching a predetermined portion of the contact layer and the second conductivity type third InP layer to form a resistor with the laser diode.

According to the present invention, resistors each having a heat generating function are provided on both sides of the laser diode. Accordingly, the wavelength of the laser diode active layer is stabilized by adjusting the amount of heat (ambient temperature) in accordance with the amount of current applied to the resistance.

EXAMPLE

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A to 2E are cross-sectional views for explaining a compound semiconductor and a method of manufacturing the same according to the present invention.

In this embodiment, in order to prevent a change in the oscillation wavelength of a planar buried heterostructure (PBH) structured laser diode, a resistor having a heat generating function is formed on both sides of an active layer of the laser diode. Accordingly, by applying a predetermined current to the resistor, the wavelength of the laser diode is stabilized by adjusting the temperature applied to the active layer.

That is, referring to FIG. 2 (a), the 1N-type InP layer 1, the InGaAsP layer 2 and the upper part of which are not doped with impurities as an active layer on the N-type InP substrate (not shown) The InP layer 3A of the 1P type is epitaxially grown by metal organic chemical vapor deposition (MOCVD). Then, a predetermined thickness of the P-type InP layer 3A, the active layer 2 made of InGaAsP that is not doped with impurities, and the 1P type InP layer 1 is etched in a mesa form to form a laser diode. You will have At this time, a grating is formed in the active layer 2 to limit a predetermined wavelength.

Thereafter, in the mesa-etched space, the second P-type InP layer 3B, the 2N-type InP layer 4, and the 3P-type InP layer 3C as the current blocking layer are sequentially epitaxially grown by the regrowth method. do. Subsequently, a P-type InGaAs contact layer 5 is epitaxially grown on the 3P-type InP layer 3C. In this case, the active layer 2 is buried by the current blocking layers 3A, 3B, 3C, and 4.

Subsequently, as shown in FIG. 2 (b), mask patterns 6A and 6B made of oxide films are formed on the contact layer 5 to limit the shape of the electrode and to limit the resistance region. At this time, the mask pattern 6A is a mask pattern for forming a P-type electrode of the laser diode, and the mask pattern 6B is a mask pattern for forming resistance for controlling heat applied to the active layer on both sides of the laser diode. The sidewall portions of the mask patterns 6A and 6B have a mesa shape.

Then, as shown in FIG. 2 (c), by the mask patterns 6A and 6B, the exposed contact layer 5 and the 3P type current blocking layer 3C are etched in a mesa form. . As a result, the laser diode region LD and the resistor R are defined.

Thereafter, as shown in FIG. 2 (d), the mask patterns 6A and 6B made of the oxide film are removed by a known removal method. Then, the contact layer 3 on the resistor R is formed in the longitudinal direction of the resistor. With respect to (X), it is patterned so as to exist only at both ends, so that a positive contact pattern 5a and a negative contact pattern 5b are formed. Further, the contact layer 5c on the laser diode region itself becomes a contact pattern of the laser diode. Here, the length of the resistor (R) is preferably formed to be the same as the length of the active layer (2).

Then, as shown in the second (e), the current blocking layers 1, 3B, 3C, and 4 outside the resistance R region are etched to a predetermined depth to form the trench 7. The trench 7 serves to electrically isolate the laser diode region with other adjacent wavelengths.

Thereafter, although not shown in the figures, bonding pads in contact with the (+) contact pattern 5a, bonding pads in contact with the (-) contact pattern 5b, and bonding pads in contact with the contact layer 5 on the laser diode. Are each formed in a known manner.

The compound semiconductor device of the present invention having such a configuration, when a predetermined current is applied to the bonding pad of the resistor R, is applied to the resistor R in accordance with Joule's law (Q∝I ² R). Joule heat is generated in proportion to the current. The heat generated in this way is transferred to the active layer 2 to adjust the wavelength in the active layer 2.

At this time, since the resistor R has the laser diode LD in the center and is spaced apart at equal intervals on both sides, uniform heat is applied to the active layer of the laser diode LD. In addition, the resistor R and the laser diode LD are spaced apart from each other at a predetermined interval so that a current applied to the resistor R is not applied to the active layer. Since the wavelength of the active layer 2 is simultaneously affected by the current and the heat, it is preferable that the current is not applied to the active layer 2, and only uniform heat is applied.

Then, since the calorific value of the resistor R is adjusted according to the amount of current applied to the resistor R, the wavelength of the active layer 2 can be easily adjusted.

Here, the present invention is not limited only to the above embodiment.

For example, although the PBH structure of the laser diode has been described in the present invention, the laser diode of the RWG (Ridge WaveGuide) structure may be similarly applied in the present invention.

As described in detail above, according to the present invention, resistors having a heating function are provided on both sides of the laser diode. Accordingly, the wavelength of the laser diode active layer is stabilized by adjusting the amount of heat (ambient temperature) in accordance with the amount of current applied to the resistance.

In addition, it can implement in various changes in the range which does not deviate from the summary of this invention.

Claims (12)

A laser diode comprising a multi-layered compound layer and having an active layer having a predetermined wavelength in the center of the compound layer, spaced and spaced at equal intervals on both sides of the laser diode, and providing a predetermined heat to the active layer of the laser diode, Compound semiconductor device comprising a pair of heat generating means to stabilize the. The compound semiconductor device according to claim 1, wherein said heat generating means is a resistor. The semiconductor device of claim 2, wherein the resistor comprises: a compound semiconductor substrate and a first blocking type current blocking layer formed on the compound semiconductor substrate; A second blocking current blocking layer formed on the first blocking current blocking layer; And a contact layer formed at both ends in the longitudinal direction of the second conduction type current blocking layer. The semiconductor device of claim 1, wherein the laser diode comprises: a compound semiconductor substrate and a first blocking type current blocking layer formed on the compound semiconductor substrate; An active layer formed on the first current blocking layer of the first conductivity type and having a predetermined wavelength; A current blocking layer of a second conductivity type formed on the active layer; And a contact layer formed on the current blocking layer of the second conductivity type. The compound semiconductor device according to claim 3 or 4, wherein the first conductivity type is N type and the second conductivity type is P type. The compound semiconductor device according to claim 3 or 4, wherein the current blocking layer of each of the first and second conductivity types is an InP compound layer. The compound semiconductor device of claim 1, wherein the active layer is an InGaAsP compound layer that is not doped with impurities. The compound semiconductor device of claim 1, wherein a length of the resistor is equal to a length of an active layer of the laser diode. Sequentially growing a first InP layer of a first conductivity type, an active layer, and a first InP layer of a second conductivity type on the compound substrate; Etching the second InP layer of the second conductivity type, the active layer, and the first InP layer of the first conductivity type to a predetermined depth to form a mesa structure; Sequentially growing a second InP layer of a second conductivity type and a second InP layer of a first conductivity type in both spaces of the mesa-type structure; Forming a third InP layer of a second conductivity type on top of the mesa structure and the InP layer of the first conductivity type; Forming a contact layer on the second conductivity type third InP layer; And partially etching the contact layer and the second conductivity type third InP layer to form a laser diode and a resistor. The method of claim 9, further comprising: after forming the resistor with the laser diode, patterning a contact layer over the resistance region so as to exist at both ends in the length direction of the resistor; And forming a bonding pad in contact with the contact layer over the patterned resistor and a bonding pad in contact with the contact layer over the laser diode. 10. The method of claim 9, wherein the first conductive tin is an N type and the second conductive type is a P type. 10. The method of claim 9, wherein the active layer is an InGaAsP compound layer doped with impurities.

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