JPS59119719A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an excellent Al1-xInxAs layer of not less than 0.1mum thickness by previously designing thickness on an InP group semiconductor substrate or a melting liquid for growth constituting an AlInAs layer to a specific value or more when the melting liquid is brought into contact with the upper section of the substrate and the AlInAs layer is grown. CONSTITUTION:An N<+> type InP clad layer 12, an InGaAsP active layer 13, a P type AlInAs clad layer 14, a P type InP clad layer 15, a P type InGaAs contact layer 16 and an N type InP cap layer 17 are laminated on the N<+> type InP substrate 11 and liquid-phase epitaxial grown, and a window is bored to the layer 17 and a P-side electrode 18 being in contact with the layer 16 is attached and an N-side electrode 19 on the back of the substrate 11 respectively, thus manufacturing the semiconductor laser device. In the constitution, the thickness of a melt for growth is brought to 1mm. or more and a growth starting temperature is selected to approximately 750 deg.C and cooling velocity to approximately 0.3 deg.C/min when the P type AlInAs clad layer 14 functioning as confining carriers is grown. Accordingly, thickness of 0.1mm. or more required for confining carriers is obtained positively.

Description

DETAILED DESCRIPTION OF THE INVENTION (al) Technical Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and in particular to a method for manufacturing a semiconductor device, and in particular, it relates to a method for manufacturing a semiconductor device.
Aa) Concerning a method of forming a layer.

(bl Conventional technology and problems
), it has a large optical intercalation effect and is a very useful crystal for producing semiconductor laser devices etc. using InP as a substrate. However, conventional All+-xlnXAs crystals have been very difficult to grow using liquid phase epitaxial growth, and in recent years it has finally become possible to grow extremely thin layers.

However, in order to construct semiconductor devices, high-quality Nll-XI
The thickness of the nxAs crystal layer needs to be about 0.1 Cμm or more, but A12. −,■nXA
It remained impossible to grow s crystals.

(C1 Object of the Invention The object of the present invention is to set the thickness h of the raw material melt for melt growth for growing the M I-X I nx As layer) such that h≧1 (nu
It is an object of the present invention to provide a method for manufacturing a semiconductor device, which makes it possible to grow a high-quality N1 (In) (As) layer to a thickness of 0.1 [μm] or more by using n).

(d) Structure of the invention The feature of the present invention is on an indium/phosphorous semiconductor crystal substrate.

Alternatively, when a predetermined growth melt is brought into contact with an indium/phosphorous semiconductor crystal layer to cause liquid phase growth of a semiconductor stacked structure including a semiconductor layer made of aluminum, indium, and arsenic, the semiconductor crystal substrate or the semiconductor layer is The thickness of the melt for growing the aluminum/indium/arsenic layer on the semiconductor crystal substrate or the semiconductor crystal layer that is brought into contact with the semiconductor crystal substrate is 1 (mm) or more.

(el Embodiment of the Invention The inventors of the present application have developed A
Q'1-xInx 'As a result of various studies regarding the growth of the As layer, by increasing the amount of growth melt sufficiently,
It has been found that M + -x Inx AsJii can be grown by liquid phase growth. That is, the reason why it was not possible to grow a thick Ml + - x Ir + x As layer using the liquid phase epitaxial growth method is because the N content in the liquid phase decreases rapidly because the N distribution coefficient is very large. Focusing on that,
An attempt was made to relatively reduce the rate of decrease in the N content in the liquid phase by increasing the amount of growth melt used. Figure 1 shows the results, where the vertical axis is the thickness h (described later) of the growth melt in the melt reservoir, and the horizontal axis is the critical growth thickness of AIL-xInxAs, that is, the high-quality A121-X that can be grown. The thickness of the Inx As layer indicates a maximum thickness at which a good quality crystal cannot be obtained even if the layer is grown thicker. The figure shows the results of liquid phase epitaxial growth at a growth temperature of approximately 780°C.

As is clear from the figure, the critical growth thickness is Alt r-x I
strongly depends on the melt thickness h for nx As layer growth;
It increases in proportion to the increase in h. Therefore thick Ml +−x
In order to grow the Ir+xAs layer, it is sufficient to increase the thickness h of the growth melt. Due to the structure of the semiconductor element, N,
The thickness of the InXAs layer usually needs to be about 0.1 [μm] or more. All' +-x I nXA of this thickness
In order to grow s1it, it was found from the same figure that the thickness h of the growth melt is required to be approximately I (mm) or more.

FIG. 2 is a sectional view showing the main parts of a growth boat used in the liquid phase growth method. In the figure, 1 is a boat base made of carbon or the like, 2 is a slider, 3 is a growth melt, and 4 is a boat base made of carbon or the like.
5 is a melt reservoir, and 5 is a semiconductor substrate to be processed, such as an InP semiconductor substrate.

In the present invention, when growing an M + -x Inx As layer, the amount of the growth melt is increased by increasing the thickness h of the growth melt 3 in the melt reservoir 4, based on the results shown in FIG. Let's make it a big thing and say "All!" +-xIn) (The ratio of the amount of N lost from the liquid phase with the growth of the As layer is made relatively small. That is, the main point is to reduce the fluctuation of the N content in the melt 3.

An embodiment of the present invention will be described below with reference to FIG. 3 while referring to FIGS. 1 and 2.

In this example, 1
1, a cladding layer 12 made of n″ type InP is disposed on top of the cladding layer 12. In
Active layer 13 made of GaAsP. Cladding layer 14 made of p-type Al2InAs. I) Cladding layer 15 made of type InP. Contact layer 16 made of p-type InGaAsP
．． This is an example in which a semiconductor laser device is manufactured by sequentially forming an n-type 1nP cap layer 17 by liquid phase epitaxial growth.

In order to form the above laminated structure on the n'-type InP substrate 11, a growth melt having the following liquid phase composition is used. Note that the compositions described below are shown in atomic ratios.

First layer: n-type 1nP layer 12 In: 0.925. P: 0.032. S
n: 0.043 2nd layer = p-type InXGa, x8s+-
y P y layer 13x=o, 3; yζ0.35 In: 0.8413. Eights: 0.1373
．． Ga: 0.0164°Cd: 0.005
0 Third layer: p-type AL-xlnXAs layer 14X=0.52 Ml: 0.0006. As: 0.1413.
In: 0.8513°cd: 0.006B 4th layer=p-type 1nP layer 15 In: 0.958. P: 0.033. Cd:
' 0.009 5th layer = p-type InxG'a (-z AS
I-y P y layer 16X#0.7; y#0.35 In: 0.8410. As: 0.1372. G
a: 0.0165°P: 0.0050. Zn:
0.0003 6th layer = n-type InP layer In: 0.958. P: 0.033.
Sn: 0.009 Third layer p-type Ml +-x
The melt thickness of the melt for growing the InxAs layer 14 is approximately 5
(mm). Also, the growth starting temperature is approximately 790C'C)
Growth is performed continuously while decreasing the temperature at a cooling rate of about 0.3 [° C.].

The growth time of each layer was approximately 700 seconds and 15 seconds, respectively.

They are 1230 seconds, 200 seconds, 60 seconds, and 40 seconds.

As a result, layers having the following thicknesses were formed on the InP substrate 11.

1st layer 20″″ type InPJit12 ・・・・・・・・・
... 3 [μm] Second layer: p-type InGaAsP layer 13
・・・・・・0.2〃Third layer: p-type MI I-x I
nX'As layer 14.0.5 4th layer: p-type InP layer 15 1.0 5th layer: p-type I
nGaAsP layer 16...0.5 6th layer: n-type 1nP layer 17...0.3 Thus, in this example, the third layer p-type Ml r −x I nX
The As layer 14 had a thickness of 0.1 [μm] or more, which is necessary for carrier confinement as a cladding layer.

A 5i02 film (not shown) having a predetermined pattern is formed on the double heterostructure wafer grown as described above, and using this as a mask, the sixth n-type InP layer 17 is formed.
is selectively removed to open a striped window with a width of about 5 μm, and then a p-electrode 18 made of gold-zinc (Au Zn) is formed. Next, the n-type InP substrate 11
An n-electrode 19 made of gold-tin (8u-5n) is formed on the back surface of the substrate. Thereafter, a semiconductor laser device is obtained by performing a fold-to-fold method to separate the semiconductor laser device into individual devices.

In the semiconductor laser device of this example obtained as described above, the heterobarrier on the p side of the active layer 13 is the p-type of the conventional semiconductor laser device! It is constructed using p-type A12 +-x InXAsnXAs, which has a larger band gap than nPJM, and moreover, p-type M)+-)<InxAsn
Since the XAs layer has a thickness of 0.1 [μm] or more, the carrier confinement effect is large. Dark value current 1 th is I th
It is expressed as oc exp (T/To), but in conventional semiconductor laser devices, To in the above equation is approximately 60 ('
K), whereas in this example, it is approximately 1oo, rK
: Increased to +, and reproducibility also improved.

Note that in the above embodiment, the active layer 1 made of InGaAsP
Although an example has been shown in which the cladding layer 14 made of At2 + -x I nXAs is provided only on one side of the substrate 3, the present invention is not limited thereto. That is, M +−x I nXA
The s-layer may be provided on either one or both sides of the active layer 13.

Further, the M I-X LnxAs layer formed using the present invention is not limited to the cladding layer of a semiconductor laser device, and At)+-X InXAs may be used for any purpose. The present invention provides an InP based semiconductor crystal substrate or an InP based semiconductor crystal layer.
It can be used in all cases of forming 2+-xInxAs layers.

According to the present invention, Ml having a thickness of 0.1 [μm] or more is grown by a liquid phase epitaxial growth method.
It is possible to grow a +-x I nXAs layer easily and with good reproducibility. Therefore, A12+-x As can be used to construct a semiconductor device using an InP crystal as a substrate, improving the characteristics of a semiconductor laser device, etc., and making manufacturing easier.

[Brief explanation of drawings]

FIG. 1 is a curve diagram showing the principle and effect of the present invention, FIG. 2 is a cross-sectional view of a main part showing an embodiment of the present invention, and FIG. 3 is a diagram showing the manufacturing process of the above embodiment and the semiconductor device obtained. FIG. In the figure, 1 is a port substrate for liquid phase growth, 2 is a slider, 3 is a growth melt, 4 is a melt reservoir, 5 is an InP semiconductor substrate (substrate to be processed), 11 is an n+ type InP substrate, 12
13 is a cladding layer made of n-type InP, and 13 is InGaAs.
Active layer made of P, 14 is p-type Ml l-X I nx
Cladding layer made of As, I5 is p-type InGaAsP
16 is a contact layer made of p-type 1nGaAsP, and 17 is a cap layer made of n-type InP. 1st rM Yan Figure 2 3rd W1 8 - Koichi

Claims (1)

[Claims] When a semiconductor layered structure including a semiconductor layer made of aluminum, indium, and arsenic is grown in a liquid phase by contacting a prescribed growth melt on an indium/phosphorous semiconductor crystal substrate or an indium/phosphorus semiconductor crystal layer. , the thickness on the semiconductor crystal substrate or semiconductor crystal layer of the melt for growing the aluminum-indium-arsenic layer that is brought into contact with the semiconductor crystal substrate or semiconductor layer is 1.
(mm) or more.