JPS58215084A - Semiconductor photo detector - Google Patents

Abstract

PURPOSE:To make the most part of holes excited in an absorption layer which is influenced particularly greatly by a hetero epitaxial junction flow into a multiplication layer at a high speed and thus contrive to improve the response speed of a photo detector by a method wherein the energy bands are positioned at three layers. CONSTITUTION:N-In0.53Ga0.47As 12, N-In1-xGaxAsyP1-y 13 (x=y/2.197, y=0.25- 0.7), and N-InP 14 are superposed on an N<+>-InP substrate 11, and a P<+> layer 15 is formed by Cd implantation into the layer 14, and a P type guard ring 16 by Be introduction, an insulation film 17 is selectively provided, and then fixed electrodes 18 and 19 are added. By this constitution, the energy band width of the layer 13 has the valve medium between that of the photo absorption layer 12 and that of the multiplication layer 14 and then selects the thickness of the layer 13, accordingly makes the minimum energy level E2 of the valence band of the photo absorption layer 12 equal to the maximum energy level E1 of the valence band of the multiplication layer 14 or higher than it in the operating state of the device. Thereby, carriers becomes easy to pass through the hetero- epitaxial junction, and therefore the response speed can be improved.

Description

[Detailed Description of the Invention] (a) Preliminary Field of the Invention The present invention is directed to improving the 5-valley speed of a hetero-evitational junction k @ tr semiconductor photodetector (b) Background light of a preliminary technique A former telecommunications company and its I-co.
In the consumer field, a semiconductor photodetector that converts a 'yt signal into a signal has become one of the important and essential constituent elements, and many have already been put into practical use or are being proposed.

vl” is silicon (Si) PIN type photodiode (PD) and Sl avalanche photodiode (AP).
D) is generally used in imperial temples with a wavelength λ of 0.85 [μ], and germanium (Ge) APDs have already been put into practical use for imperial courts with wavelengths λ = 1.3 [μ].

However, since there are limits due to the quality of the material, for example in the future 7c retrograde flow and noise, the development of support devices using compound semiconductors is progressing.

As these compound semiconductors, for example, the above-mentioned growth λ-
For the 1.0 to 1.7 [μ] band, indium
Gallium Arsenic 1 (InGaAs), Innoum
Gallium, arsenic, phosphorus (InGaAsP) + gallium aluminum, antimony (GaA14S b')
, gallium aluminum, arsenic, antimony (GaA1
4Sb') etc., and for approaching the visible wavelength band, gallium aluminum arsenic (GaAI!As)-4
is used.

(e) Prior Art and Maike Point The APD is shown in FIG. 1 as -ψ1] of the ten-conductor light-receiving system formed by these combined proboscis bodies.

In Figure 1, 1 is +1” m I nP 4 more, 21
'j n 2InGaAs light absorption layer, 3 is nm I
n P jJ times! , 4 is an f-hole formed on the InP layer, 5 is a p1 with a guard ring effect, 6 is an absolute Tpe,
暎, 7 yi P = i1' = Fusuma, 814 n @ Seikoku.

Ni to this APD! By applying a reverse bias magnetic pressure with 1114 years old 8 as positive and p side pole 7 as voice 7, p
A depletion, rj, is formed near the interface between the n junction, that is, the p+ layer 4 and the n-type InP layer 3, and this is the n-type InGaA
s spreads in the light absorption layer 21, and within this depletion layer, the input light excites Naruko to the 4th stage, and the side surface 8. The hole is pXi
l' quadrupole 7: control and drift, n-type InP multiplier layer 3
When P is present, avalanche multiplication due to holes with and occurs.

The energy control of APD explained above is shown in Figure 2 (a) and (
b). However, 2J(a) shows the state where no bias voltage is applied, and FIG. 2(b) shows the state where bias and pressure are applied. Each part of the four bodies is represented by Ec, the conduction band, and Ev, the value.

As seen in these figures, n-type InGaAs light absorption B
In 2, the forbidden band transition is narrow and the n-type InP seat fold 3';-'i forbidden band width is wide, so there is a step in the transmission band Ec and the valence band Ev at the heteroepitaxial junction interface between the two. arise.

As mentioned earlier, the n-type InGaAs optical absorption layer 2 splits the input signal light to generate four electron-hole pairs, and furthermore, in the n-type InP multiplication layer 3, an avalanche of electrons and holes is generated by multiplying pM. Hole pairs are generated, but these excited 7 electrons move toward the n-side polarity 8 in the propagation band 71, and the hole 71 which is picked up by returning
=-Koei can be used to drift p's 'i-''''7. However, these four electrons/holes, or carriers:
Furthermore, the above-mentioned step difference in the energy portion at the contact interface of the heteroepitaxial layer: ・ζ Therefore, the energy is taken away and the Mk thereof decreases. This speed reduction is sometimes noticeable for holes.

This decrease in carrier speed is due to the 1,400-year-old Ukemotojuku λ, for example ILi
In the modified station wave and output Kerr flow characteristics of input i3 of APD, Fig.
)≠30 [J4Hz] Appears as a decrease in the output current.

Countermeasures known to those skilled in the art in order to achieve this frequency enhancement: ・The absorption of the light absorption factor, i.e. the excitation of the carrier, ・5 is the redundancy. The carriers generated are at the maximum at the interface and decrease from 17 to 17 according to the depth of incidence, so the generated carriers reach the interface. ”
Taking advantage of the fact that there are many things that require less energy to reach This is a method of increasing the energy of carriers that reach the interface. However, this approach has not yielded sufficient results, and there is a need for the development of a more accurate technique.

(d) Object of the Invention The present invention improves the response speed, frequency, etc. of a 4 giL photoreceptor length device including a heteroepitaxial junction by facilitating the passage of carriers through the heteroepitaxial junction. The purpose is to

(e) Groove bottom of the invention The above-mentioned item 3) of the present invention is characterized in that the first dry-damage layer of the first 4 layers is made of a necessary prefecture 111 belt and the light absorption layer is groove-bottomed. a second semiconductor layer having a first conductivity type provided in contact with the second semiconductor layer; a third =S body layer of a first conductivity type, and a fourth semiconductor layer of a second conductivity type provided in the third semi-moving body; The prefectural total of the semiconductor layer of 2 is equal to or more than 4 percentage width of 1 child of 41, and the former j is ≦ 3, 4; gCows that are less than the width of the current emperor 4
This is achieved by the salary receiving device.

(f) Application of the invention The invention will be specifically explained below using examples with reference to the drawings.

FIG. 4 shows an APD'f which is a first embodiment of the present invention.

In FIG. 4, 11 is the n-type InP-iIf version, 12
．． ln-type I nGaAs light absorption layer, 13 is n-type I nGaAsP Tri, which is a feature of the present invention, and 14 is n f
InP N'rFf layer, 15. is p-domain, 16. The p range that takes on the ogard ring effect, 17 is the p range, and the p range is 119.

The APD of this embodiment is manufactured, for example, as described below. That is, n-type IncLs3 is formed on the n-type InP plate 11.
Gao47As layer 12 is carrier@degree IX 10" to IX 10" (5-3), thickness 2 (a -] aU
, n-type I nl-X (JaX Asy Pl-7 layer 1
3 (however, x=y/2.197.y=0.25 to 0.7
degree) Total carrier concentration 1×1014 to lXl0” (c
m-3), Rhinoceros 05 to 1 [μ genus] Katsurayu, nWInP
r$14f Chiyaria DaLXIQ”~lXl0”Cc
ll-'L 4s2 to 4 C1' wing] m'XK,
, the above-mentioned n-type In
P layer 14v 91! By selectively converting sword domium (Cd), carrier d degree 1 x 10'8+- [ca 1 degree, thickness 1 to 2 [μ] degree p value castle 1 is obtained.
For example, a PD region 16 serving as a guard ring is formed by adding four beryllium (Be) layers. Therefore, the insulating film 17 is formed in the selected iJ, and then the insulating film 17 is formed in the p.
For example, gold-zinc (AuZn) is used to provide the n-side bottom electrode 19, and the n-side bottom electrode 19 is provided using, for example, pot-glumanium (AuGe).

In "

-z G az A sy P The profit margin of the 1-7 layer 13 is n'r I no, s・3GaOL47A
If we take one line between the S light absorbing layer 12 and the nm I nP layer M14 and illustrate the working force of each of these layers, we can see that when no bias pressure is applied, Figure 5 ( a
), 45td(b) when the bias-pressure is stamped υ
and nmIn+ =xGaXAsyP+-
By this, we are approaching the enjoyment of the Y layer 13.
2 in 1 state, n'5fb■n01s 3Gacn
? The lowest energy premature formation E of the .l'J-44 molecule bonding of the As light absorption layer 12 is expressed as the highest energy quasi hf E + of the valence band of the n-type InP%J, - 14: Ha?;
It's flat.

As explained above, these three layers of energy forces are
r i' (Due to V, the chromatic tube of the heteroevital junction layer is particularly thick in the original absorption layer 12; most of the released holes are transported to Ruse 1114 at high speed. Become.

A second uninvented example, which is a further modification of the first embodiment to Vζ, will be described. The LTT surface of the second contract tl was originally shown in the first example 4
Same as Figure 4, but with n-ligated InGa as @characteristic of the present invention.
Structure of AsP row 13, and t-different:C.

That is, 42 A m'i'l n-type Ink-XG
aXAsyPI-yJ413 is n-type Ino, 53Gal
1L47Asf In the case of the 12-year-old Aishi Temple, its composition is In o, s 3 Ga O, 47 AS Ding, that is, Inws 3 Gao 47 As +, ooPo, and there is only one lattice match (not 4 but a thread line). are also consistent, and their evolution during epitaxial growth is shown by the dots in Figure 6.
Therefore, x = 0.47 → O,
y=1. By changing OO→0 to 7, the prefectural band width is gradually expanded, and in the IntooGaoAsoP layer 14 in contact with the n-type InP layer 14, its composition becomes IntooGaoAsoP.
In other words, the forbidden band width is also matched as InP. The thickness of this layer 13 is selected to be the same as that of the 10th embodiment.

However, Fig. 6 ti I nl-xGaXAsyPt-
A set of 2 lattice constants and forbidden band widths in a y-mixed crystal with 7 digits:
This is a table that clearly shows this.The horizontal and small axes represent the set, d ratio τ, ≦Tai-Kou's actual win indicates the forbidden band width, and the broken line indicates the lattice constant.

2. The n-type In1-xGaXAsyPl- explained above
y) Threat 13 is molecular beam crystal growth (&Iolecular
It can be formed by the Beam L'pi-taXy=%iBE) method, vapor phase deposition, etc.

This second example of energy is illustrated, q-j-1, bias-pressure is not applied, Figure 7(a), bias-4 pressure is applied and it is 71;,! (Like bl, nff1Ino, 53Gao47A3 light absorption layer 12 and n-type InP 4 times, j14 is n d I n+
-zGaxAsy P+, 7 layers 13, mechanical characteristics: - Since the layers are smoothly continuous without any peaks or valleys, carriers flow in without being attenuated.

Based on the first implementation example and the second example V, we determined the modulation frequency of the input signal and the output current to the same method as the North American product. ΔIIHz)
It was confirmed that all of the pieces were carefully custom-made.

The above cusp L1 example is an APD with an avalanche Ruko layer, but the photodiode (PO) that does not take on the avalanche accommodation effect
Even if you get stuck, you can get the same effect by using non-invention.

However, the above N t = fll is 1nGaAs/InP
Although it uses materials and materials, it is uninvented (-), and it is not mutually exclusive, and it is P +
It is possible to pass for children, 7ta, English, 7i! l
Even if the Ukemotoke jl is combined with the Den 4 type, which is the opposite of the Den 4 type of I Nori, the same effect can be obtained.

(g) Effects of the Invention According to the present invention, the deceleration of carriers caused by the above-described heteroepitaxial junction of the dt double phosphor device makes Mm or i'' quiet. The response becomes faster and the modulation frequency σ-output-current ratio of the original input signal is greatly improved.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a conventional example of a semi-quadruple light receiving device, Fig. 2 (a) and (b) are views showing its energy range, and Fig. 3 is its modulation frequency-output flow chart. Chart showing peaks, 4th
The figure is a sectional view showing an embodiment of the invention, Figures 5(a) and (
b) (Diagram showing the energy band of IJ in the first implementation, Part 6)
Is 0 an InGaAsP fart crystal? A diagram showing the correlation between the composition of the Sukushi Akiao and the width of the thread belt width. 1 is n”F4 I nP bracket'f2.2 is n-type InGaAs redundant absorption layer, 3 is n-type I nP h,
'i ffl 1tli, 4fdp' area, 11 is n+
fi I n P Ma, 12 is an n-type InGaAs light absorption layer, 13 is an n-type In Ga As P layer, 1
4 is a nuInP layer, 15 is a p+ region 16 is a guard ring, 17 is an insulating film, 18 is a p layer, 19 is an n layer 114
Indicates 0. L Pyo No. 1121

Claims (1)

[Claims] A first conductive type shoulder sieve body, which has a uniform band width and forms the entire absorbing layer, and a first conductive layer provided in contact with the first semiconductor layer. Has a type. H2 semiconductor layer, and the first -i! provided in contact with the second semiconductor layer. = 7 layers larger than the 1st layer; a fourth semiconductor of the type C1, and the profit margin width of the 20th half 4th layer is equal to or greater than the system band width of the 1st middle 4th layer of MiJ, and the third semiconductor Genkei smoked with 4 cows, which is characterized by being below the prefectural level of the prefecture.