JPS6139514A - Manufacture of gaalas semiconductor device - Google Patents

Abstract

PURPOSE:To prevent an electrically connected part from making inroad into the region of an indirect transition as well as to enable to manufacture a GaAlAs light-emitting diode device of excellent light-emitting efficiency by a method wherein the second P- layer of low acceptor impurity density is provided between the first P-layer and an N- layer. CONSTITUTION:The first p-layer 11 is grown by contacting a Zn-added GaAlAs melt to a p-type GaAs substrate by performing a liquid phase epitaxial growing method, and then the second p-layer 12 is grown by contacting the GaAlAs melt, wherein Zn added in the quantity less than the above-mentioned added quantity of Zn, to the first P-layer 11. Moreover, an n-layer 3 is grown by contacting a Te added GaAlAs melt to said layer 12. Consequently, although the Te of the n-layer 3 is diffused in the second p- layer 12, it can be adjusted on the composition interface J, because the degree of the above-mentioned diffusion is lower than the diffusion of Zn. If the effect of compensation is taken into consideration on the composition interface J of the second p-layer 12, namely, the p-layer 13 and the n-layer 3, the density of carrier becomes NA=ND on the composition interface J, the electrically connected part J' and the composition interface J are coincided, and an excellently efficient light-emission can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides G a A by liquid phase epitaxial growth method.
The present invention relates to a method for manufacturing epitaxial wafers used in Otori As light-emitting diodes.

2. Description of the Prior Art Generally, when manufacturing a GaAlAs light emitting diode device, as shown in FIG. P-nf & gJk were obtained by epitaxial growth. Usually, Zn is used as the acceptor impurity to form the second layer 2, and Te1 is used as the donor impurity, and the Cn layer 3 is sequentially lengthened in the direction of the dotted arrow 4 &CrIyt.
The P layer 2fn layer 3 is intended for window effect]. At this time, the composition of the completed Evita is determined, and the mixed crystal ratio of the multilayer is set as follows: ．． 35.1 layer is 3C=0.65
Z (J a 1.1- XA g N
A-3 was adjusted to melt to obtain a crystal with a predetermined degree of roughness added to Zn or Te1, respectively, and was used to enhance the luminescence or window effect.

In particular, the P layer is the luminescent center and its Zn concentration cape is directly attached.
Ru. Zn in the melt evaporates easily, and the amount of Zn in the crystal depends on the amount of Zn added to the melt and the growth equipment.

Although it depends on the growth process etc., for example, Zn in the melt
:0. +5mo1% and the Zn concentration of the rotten crystal is 2Xl
', o 18 -3CIn.

In addition, Ga is sometimes used as an acceptor impurity, but in order to increase the acceptor concentration, multilayer Lje
&)' Zn is usually used because it has the drawback that lattice defects increase when added to the melt.

Temperature variation ratio of dopant diffusion and segregation coefficient in the above PH4, 1 layer: No congratulations, P, assuming that the composition change in the 1st layer is good, the growth direction is 4 as shown in Figure 4. The distribution of acceptor degree NA and donor degree N should be constant.

However, like Ge, Zn is used in a process that increases lattice defects.
1 has no drawbacks, but its diffusion coefficient is large and its expansion F! ! L.J.
Due to temperature changes in the P composition, NA and ND produce a gk degree gradient in the growth direction, and Zn crosses the P-n junction Ji.
Diffused distribution in layers? Take.

Nh, N0c)) If we focus on the P-n junction JK at the t'' ratio, as schematically shown in Figure 5, the Zn concentration NNA diffuses beyond the junction J to the 0 layer 3, as shown by the solid line 5. is the distribution, and the Te bell fgLND of n Jt!I is
The part indicated by the dashed line in the growth direction 4 is taken as −(+i 'at.The part where these two dense summer distributions Nmu and ND overlap is a compensation young fruit, and the one with the largest difference becomes the carrier, and it is observed that is,
The apparent carrier distribution 5 is shown by the dashed line.

Therefore, the compositional boundary J between the direct transition region and the indirect transition region
' and the actual electrical connection J'.

-゛ Since the electrical junction J' exists in the region of indirect transition, the luminous efficiency is extremely low.

The problem to be solved by the present invention is @G
In order to manufacture an aAlAs light emitting diode device, it is possible to prevent the electrical junction from digging into the region of indirect transition.

A means to solve the problem is to grow the 11' layer by adding Zoom as an acceptor impurity on the P-type GaAs substrate by liquid phase epitaxial growth method and growing the 11' layer in contact with the LP layer using rK. G a A J A with less Zn added than the above Zn addition amount
G2P/it was grown by contacting S melt, and then Te was added as a donor impurity on top of it.
This is a method of growing one layer by bringing AIAs melt into contact.

Therefore, as shown in FIG. 1, % tp layer [l.

g2PJlj12 When epitaxially growing layer 3, the same amount of AI as before was added to layer 3.
G a - G a As - A 1 melt was used to form the LP+! on the substrate. The 'abX lengthened melt is grown with Zn added thereto.Next, on top of this L)'/* layer, a Zny-added melt with a smaller amount than that of the melt used in growing the tt' layer is added to increase the thickness. :L~2μm second Plfi
1), and then grow the same 1 as before on 42P) II.
Grow layers.

At this time, Zn at t)'+ntt also diffuses into m2PI so L2, so the melt in the growth phase of @2P layer L2 contains only a small amount of Znv, or all of it (even if it does not fit, P
IdL3 is obtained. As for vclit.

- A known slide boat for multilayer growth is used.

When the LP layer is grown by the above operation, after the growth M, the acceptor concentration NA of the first P layer jL is at a high level, but it is diffused during the growth process of the second P layer 12 and the first layer. The level gradually decreases. The acceptor concentration of the second P layer 12 is at the same level as the donor a degree at the interface between the second P layer [2 and nA13].
! Reba (.

Since Zn diffuses from the first P layer 11, the variation of Zn in the second P layer melt is extremely small (a melt containing no Zn4 may be used).
, NJ)'s preferred level A1 B-3, NA: L ~ 3XLOcm, ND: 5
~LOXIOcm.

If the growth is performed as described above, the “re” of n#3 will also become the second P.
Although it diffuses into layer [3], it is small compared to the diffusion of Zn, so
The composition interface JK, can be adjusted at the second PjtjlL2,
In other words, IP11P￥1! [Compensation effect at the composition interface J between 3 and 0 layer 3? Considering vd, the Kiria concentration becomes NA:ND at the compositional interface J, and the iml gas junction J
' and the compositional interface J coincide, and efficient light emission occurs.

Example [Example] On a P-type GaAs substrate, the melt shown in Table 1 was used to sequentially grow the IP7d, the second P layer, and the layer n1.

Table 1 The operating conditions are as follows: Using a multilayer slide boat a-phase Ebitaki 7-yel growth fCm, after incubation at 820°C for 60 minutes, a P-type layer a
The temperature was lowered at a rate of iL, 0, 3 °C/min, and the second LPJ! 'v grow, 7966CVC1K'
)T: In ToC, the melt for forming the second P layer is placed on the first P layer, the temperature is lowered to 795°C to grow the second P layer, and the second P layer is grown at 795°C. An n-layer was grown on top using a melt V apparatus for n-layer formation. The thickness of the epitaxially grown layer is 25 μm for the Ll′ layer and 1 μm for the second P layer.
μm, and the n-layer was 28 μm. Also.

When the carrier hardness vQIJ was determined, the NA was 2.0XLOcm near the P-n junction.

('JD Winter 5, 6 XLOCtn Atta.

It was confirmed that the compositional interface of this semiconductor matched the EBIC image (electrical junction J') in a Scan Jung Electron Microscope (C8HM). tt' layer, second P layer S and nWIY sequential growth, thickening of fake, first Plfl
: 24 μm, m2 PjvI: 2 μm, n-layer: 26 μm, but the same as Example [Example].

Table 2 also shows that the carrier resistance is 1g near the P-n junction.
-3- NAAl1.6X L g cm, Ni
'? Ivy 3 5.0XlOcm.

It was confirmed that the compositional interface of this semiconductor also coincided with the same t4EBIc image as that of Example [Rimono].

4 used for comparison of Example 20, a half-body (light-emitting diode), a light-emitting diode without a second P layer made by a conventional method, and a normal light-emitting diode.
When compared by a hardness measurement method, it was confirmed that the one made by the uninvented method clearly showed a higher cutting edge.

Specifically, in numerical terms, the light emission output at the peak wavelength: 57Q, nm is as shown in FIG.
It shows 1.37 times the luminous output and is produced by an uninvented method (taking into account the compensation effect at the compositional interface of the leaked light emitting diode, y5NA, N, and D are N = ND).
It can be seen that it is.

Effect of non-invention As mentioned above, regarding non-invention (#a A J A
In the S-light emitting diode, since the second PI with low acceptor impurity donation is provided between the 4TLP scrap and the n-layer, diffusion of the acceptor impurity of the P-type layer into the n-layer is suppressed, making it possible to reduce the possibility of an early stage. The 1U air conditioner that I considered was nJ.
A GaAlAs semiconductor device with S sieve degree can be obtained without encroaching into the ψ.

[Brief explanation of the drawing]

Fig. 1 is a detailed explanatory diagram of the present invention;
The figure shows a comparison of the light emitting output of semiconductors produced by the fE method and the method of the present invention. The figure is a 61 analysis diagram of a semiconductor, Figure 4 is a virtual diagram of an ideal carrier distribution, and Figure 5 is a state in which the electrical junction is n ) dIc A - B! This is a clear diagram. [... board, 3... n increase, 4...
...Light direction. 11...th [P layer, I2...2nd P shield, [3...P) dl, N people...Accessor impurity (Z n ) concentration , ND... Donor impurity (TeJ Isodo, J... p-n junction (composition interface), J'... electrical junction. 7-Boshin, +5 Uguri J'Mome Fuda's Stop 4 Seasons Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] GaAl with Zn added as an acceptor impurity by liquid phase epitaxial growth on a P-type GaAs substrate
A first P layer is grown by bringing an As melt into contact with the first P layer, and then a GaAlAs melt to which Zn is added in a smaller amount than the above Zn addition amount is brought into contact with the first P layer to grow a second P layer.
Furthermore, Ga is added with Te as a donor impurity.
A method for manufacturing a GaAlAs semiconductor device, characterized in that an n-layer is grown by contacting with an AlAs melt.