JP2670553B2 - Semiconductor light receiving / amplifying device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light receiving / amplifying device having a configuration in which a photodiode as a light receiving element and a field effect transistor as an amplifying element are integrated. 2. Description of the Related Art Conventionally, a semiconductor light receiving / amplifying device having the structure described below with reference to FIG. 6 has been proposed. That is, n is formed on the semi-insulating semiconductor substrate 1 made of InP.
A semiconductor layer 2 of InGaAs type having a low carrier concentration and a low concentration is formed, and a semiconductor region 3 having a P type is formed in the semiconductor layer 2 from the side opposite to the semi-insulating semiconductor substrate 1 side. A semiconductor region 4 that has been formed and also has P-type is formed. Further, on the semiconductor layer 2, a window 5 that exposes the semiconductor region 3 to the outside, a window 6 that exposes the semiconductor layer 2 to the outside in the region between the semiconductor regions 3 and 4, and a window that exposes the semiconductor region 4 to the outside. An insulating film 9 for surface protection having a window 7 for exposing the semiconductor layer 2 to the outside in a region outside the semiconductor region 4 is formed. Further, an electrode 11 having a window 10 is connected to the semiconductor region 3 through the window 5, and the semiconductor layer 2 has windows 6 and 8.
Electrodes 12 and 13 are connected to each other,
Further, the electrode 14 is connected to the semiconductor region 4 through the window 7. Then, the semiconductor layer 2, the semiconductor region 3, and the electrodes 11 and 12 constitute a PN junction type photodiode D having the semiconductor layer 2 as a light absorbing layer and the electrodes 12 and 11 as an annot electrode and a cathode electrode, respectively. A so-called column gate type PN having the semiconductor layer 2 as an active layer, the electrodes 12, 13 and 14 as a source electrode and a drain electrode gate electrode respectively by the layer 2, the semiconductor region 4, and the electrodes 12, 13 and 14.
A junction field effect transistor T is constructed. The above is the configuration of the conventionally proposed semiconductor light receiving / amplifying device. According to the semiconductor light receiving / amplifying device having such a configuration, in a state where a load is connected between the electrodes 11 and 12 via the bias power supply, the light L is transmitted through the window 10 of the electrode 11 to the PN junction type photo. When the diode D is irradiated, the light detection output is output from the PN junction type photodiode D to the load, and another load is connected between the electrodes 12 and 13 via a bias power supply. By supplying the photodetection output described above between the electrode 14 and one of the electrodes 12 and 13, the amplified output controlled according to the photodetection output is a so-called column gate type PN junction type. A light receiving / amplifying function of outputting from the field effect transistor T to the load can be obtained. However, the conventional semiconductor light receiving device shown in FIG. In the case of the amplifying device, since the active layer of the PN junction field effect transistor T and the light absorption layer of the PN junction photodiode D are composed of the semiconductor layer 2 common to them, the semiconductor layer 2 is Assuming a high carrier concentration, which is desirable for the active layer of the PN junction field effect transistor T, the semiconductor layer 2 has a high carrier concentration which is undesirable for the active layer of the PN junction photodiode. Further, in the PN junction type photodiode D, since the depletion layer from the PN junction between the semiconductor layer 2 and the semiconductor region 3 to the semi-insulating semiconductor substrate 1 is easily achieved, the photo carriers generated in the depletion layer absorb light. It has a horizontal structure in which the light receiving function as a photodiode is obtained by moving the semiconductor layer 2 as a layer in the lateral direction by a long distance. For this reason, the conventional semiconductor light receiving / amplifying device shown in FIG. 6 has a disadvantage that the light receiving / amplifying function cannot be obtained at a high speed. [Means for Solving the Problems] Accordingly, the present invention is to propose a novel semiconductor light receiving / amplifying device that does not have the above-mentioned disadvantages. The semiconductor light receiving / amplifying device according to the present invention comprises (1) a first semiconductor layer having n-type and InGaAs and a first semiconductor layer having n-type and being made of InP on a semi-insulating semiconductor substrate made of InP. Two
And a semiconductor layer of
(2) A fourth semiconductor layer having n type and InGaAs and a fifth semiconductor layer having n type and InP are formed on the third semiconductor layer. Forming a sixth semiconductor layer in which and are laminated in that order, (3)
A first semiconductor region having p-type is formed in the third semiconductor layer from the side opposite to the semi-insulating substrate side,
A PN junction field effect transistor having the first semiconductor layer as an active layer is configured. (4) The sixth semiconductor layer has a p-type from the side opposite to the third semiconductor layer. A second semiconductor region is formed to constitute a photodiode that can be regarded as a PIN junction type, in which the fourth semiconductor layer is used as a light absorbing layer. According to the semiconductor light receiving / amplifying device of the present invention having the above-described configuration, by causing light to enter the photodiode, the light detection output is output from the photodiode, and the light detection output is output. Is supplied to the PN junction type field effect transistor, the light receiving / amplifying function of outputting an amplified output controlled according to the photodetection output from the PN junction type field effect transistor is obtained. In this case, since the active layer of the PN junction field effect transistor and the absorption layer of the photodiode are respectively composed of the first and fourth semiconductor layers different from each other, the active layer of the PN junction field effect transistor is , The absorption layer of the photodiode may have a desired high carrier concentration, and the absorption layer of the photodiode may have a desired low carrier concentration, and in the photodiode, it may have a PN junction. It can be regarded as a PIN junction type instead of a shape, and
Since the photocarrier has a vertical structure in which the light receiving function as a photodiode can be obtained only by moving the absorption layer in the vertical direction by a short distance, the light receiving / amplifying function is described in FIG. Compared with the conventional semiconductor light receiving / amplifying device, it can be obtained at a significantly higher speed. In addition, the semiconductor layer of FIG. 3 has a second semiconductor layer of InP formed thereon in addition to the first semiconductor layer of InGaAs system, and the sixth semiconductor layer is of InGaAs type. Since the semiconductor device has the fifth semiconductor layer made of InP formed thereon, in addition to the fourth semiconductor layer made of a system, the surface leak current in the field effect transistor and the photodiode is extremely small, and therefore, the light receiving -Amplification function can be obtained as an extremely low noise free one. Further, a sixth semiconductor layer is formed on the third semiconductor layer, and the second semiconductor layer of the third semiconductor layer on the semiconductor layer side in FIG. 6 is made of InP. When the layer is to be formed into a mesa shape by etching the sixth semiconductor layer, the layer can be a stop layer for the etching processing, so that the sixth semiconductor layer can be easily formed into a mesa shape. Further, since the first semiconductor layer of the third semiconductor layer as the N layer of the photodiode has a configuration in which the first semiconductor layer is the semiconductor layer as the active layer of the PN junction field effect transistor, it is formed on a semi-insulating semiconductor substrate. The number of semiconductor layers can be reduced, so that a light receiving / amplifying function can be obtained with a simple structure, and a semiconductor light receiving / amplifying device can be easily manufactured. First Embodiment Next, a first embodiment of the semiconductor light receiving / amplifying device according to the present invention will be described with reference to FIG. The semiconductor light receiving / amplifying device according to the present invention shown in FIG.
For example, on a semi-insulating semiconductor substrate 11 made of InP, a first semiconductor layer 12 having n-type and made of InGaAs is similarly n-type and has a larger forbidden band width than the semiconductor layer 12. InP
And the second semiconductor layer 13 is formed in this order to form the third semiconductor layer 14. Also, on the semiconductor layer 14 of FIG.
A fourth semiconductor layer 15 made of As system and a fifth semiconductor layer 16 made of InP which also has n-type and has a larger forbidden band width than the semiconductor layer 12 are laminated in that order. The sixth semiconductor layer 17 of the structure is locally formed in a mesa shape. In addition, in the third semiconductor layer 14, a first semiconductor region 22 having a p-type is formed from the side opposite to the semi-insulating substrate 11 side.
Is formed to a depth reaching the semiconductor layer 12. Further, a p-type second semiconductor region 21 is formed in the sixth semiconductor layer 17 from the side opposite to the third semiconductor layer 14 to a depth reaching the fourth semiconductor layer 15. . Also, a window 31 extending through the third semiconductor layer 14 and the sixth semiconductor layer 17, extending therethrough, and exposing the second semiconductor region 21 to the outside, a fifth window of the semiconductor layer 17 of FIG. The semiconductor layer 16 is exposed outside the second semiconductor region 21, and the fourth semiconductor layer 15 of the sixth semiconductor layer 17 is exposed outside in the region between the fourth semiconductor layer 15 and the second semiconductor region 22. To expose the first semiconductor region 22 to the outside, and to expose the second semiconductor layer of the third semiconductor layer 14 to the outside in the region outside the first semiconductor region 22. Window 34
And a surface protection insulating film 35 made of, for example, SiN ₄ is formed. Further, the electrode 41 having the window 36 is connected to the second semiconductor region 21 through the window 31, and the fourth and fifth semiconductor layers of the sixth semiconductor layer 17 and the second semiconductor layer 14 of the third semiconductor layer 14 are connected. An electrode 42 is connected to the semiconductor layer 13 of
An electrode 43 is connected to the semiconductor region 22 through a window 33, and an electrode 44 is connected to the second semiconductor layer 13 of the third semiconductor layer 14 through a window 34. Then, the second semiconductor layer 21 is formed by the first and sixth semiconductor layers 14 and 17, the second semiconductor region 21, and the electrodes 41 and 42.
Is a P layer, the fourth semiconductor layer 15 of the sixth semiconductor layer 17 is a light absorption layer, the third semiconductor layer 14 is an N layer, and the electrodes 42 and 41 are anode and assole electrodes, respectively, and is a PIN junction type. A photodiode D that can be regarded is constructed. here,
The reason why the photodiode D can be regarded as a PIN type is that the N-type fourth semiconductor layer 15 of the sixth semiconductor layer 17 is replaced with a 5 × 10 ¹⁵ cm ⁻³ as will be described later. A carrier concentration sufficiently lower than that of the first semiconductor layer 12 of the third semiconductor layer 14 as the N layer, which can have a high carrier concentration of 2 × 10 ¹⁷ cm ^−3. Can, for this reason, its fourth semiconductor layer
This is because 15 can be regarded as the I layer. In addition, the third semiconductor layer 14, the second semiconductor region 22, the electrode
The PN junction field effect transistor T having the second semiconductor layer 12 as an active layer and the electrodes 42, 44 and 43 as a source electrode, a drain electrode and a gate electrode, respectively, is constituted by 42, 43 and 44. The above is the configuration of the first embodiment of the semiconductor light receiving / amplifying device according to the present invention. In practice, the semiconductor light receiving / amplifying device having such a structure can be manufactured by the method described below with reference to FIG. 2 in which the same parts as those in FIG. . That is, on the semi-insulating substrate 11, the first and second semiconductor layers 12 and 13 forming the third semiconductor layer 14 and the subsequent fourth layer are formed.
And the semiconductor layers 15 'and 16' constituting the semiconductor layer 17 'to be the mesa-shaped sixth semiconductor layer 17 consisting of the fifth semiconductor layers 15 and 16 are formed in that order by, for example, a molecular beam epitaxial growth method. (Fig. 2A). Next, the semiconductor layer 17 'is subjected to, for example, a wet etching process known per se using a mask to form a mesa-shaped sixth semiconductor layer 17 from the semiconductor layer 17' (FIG. 2B). ). In this case, the semiconductor layer 13 made of InP of the semiconductor layer 14 under the semiconductor layer 17 'acts as a stop layer for the etching process, and thus the mesa-like semiconductor layer is formed.
17 can be easily formed. Next, looking through the third and sixth semiconductor layers 14 and 17, and extending over them, the window 31 for exposing the sixth semiconductor layer 17 to the outside, which becomes the insulating film 35 for protecting the surface thereafter, Insulating film 35 'having a window 33 that exposes the third semiconductor layer 14 to the outside.
And then, in the sixth and third semiconductor layers 17 and 14 by, for example, implantation of P-type impurity ions known per se, followed by annealing treatment, to form second and first semiconductor regions 21 and 22. Are formed (FIG. 2C). Next, on the insulating film 35 ', the sixth and fourth semiconductor layers 17 and
A window 32 that exposes 14 to the outside and a window 34 that exposes the third semiconductor layer 14 to the outside are formed, an insulating film 35 'is formed from an insulating film 35', and then electrodes 41, 42, 43, and 44 are formed. Is formed by a method known per se to obtain the semiconductor light receiving / amplifying device shown in FIG. According to the semiconductor light receiving / amplifying device of the present invention shown in FIG. 1, the light L is transmitted through the window 36 of the electrode 41 to the photodiode while the load is connected between the electrodes 41 and 42 through the bias power supply. When D is irradiated, the photodetection output is output from the photodiode D to the load, and the electrodes 42 and
By supplying the above-described photodetection output between the electrode 43 and one of the electrodes 43 and 44 while connecting another load via another bias power supply between the electrodes 44 and 44, Obviously, the light receiving / amplifying function of outputting the amplified output controlled according to the light detection output from the PN junction field effect transistor T to the load is obtained. In this case, the PN junction field effect transistor T
Of the third semiconductor layer 14 and the fourth semiconductor layer 15 of the sixth semiconductor layer 17, which are different from each other. Therefore, the active layer of the PN junction field effect transistor T is
It may have a carrier concentration as high as 2 × 10 ¹⁷ cm ⁻³ , which is desirable for it, and the light absorbing layer of the photodiode D may be made as high as 5 × 10 ¹⁵ cm ⁻³ , for which it is desirable. It can have a low carrier concentration, and it is considered to be a PIN junction type in the photodiode D,
Moreover, since the carrier has a vertical structure in which the light receiving function as the photodiode can be obtained by merely moving the fourth semiconductor layer 15 as the light absorbing layer in the vertical direction by a short distance, Compared with the case of the conventional semiconductor light receiving / amplifying device described above with reference to FIG. 6, it can be obtained at a significantly higher speed. In addition to the first semiconductor layer 12 made of InGaAs, the third semiconductor layer 14 has a second semiconductor layer 13 made of InP formed on the first semiconductor layer 12 and having a larger forbidden band width than that of the first semiconductor layer 12. Also,
The sixth semiconductor layer 17 is an InGaAs-based fourth semiconductor layer 15
In addition, the fifth semiconductor layer 16 made of InP having a larger bandgap than that formed thereon and having a larger forbidden band width than that of the field effect transistor T and the photodiode D
The leakage current is extremely small, and therefore, the light receiving / amplifying function can be obtained with extremely low noise. Further, the sixth semiconductor layer 17 is formed on the third semiconductor layer 14, and the sixth semiconductor layer 17 of the third semiconductor layer 14 is formed.
Since the second semiconductor layer 13 on the side is made of InP, when the second semiconductor layer 13 is formed into a mesa shape by etching the sixth semiconductor layer 17, it should be used as a stop layer for the etching treatment. Therefore, the sixth semiconductor layer 17 can be easily formed in a mesa shape. In addition, N of the photodiode D that can be regarded as a PIN junction type
The first semiconductor layer 12 of the third semiconductor layer 14 as a layer is PN
Since the structure is a semiconductor layer as an active layer of the junction field effect transistor T, the number of semiconductor layers formed on the semi-insulating semiconductor substrate 11 can be reduced, and thus the light receiving / amplifying function can be simplified. The structure can be obtained, and the semiconductor light receiving / amplifying device can be easily manufactured. [Embodiment 2] Next, referring to FIG.
A second embodiment of the amplification device will be described. In FIG. 3, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. The semiconductor light receiving / amplifying device according to the present invention shown in FIG.
In the semiconductor light receiving / amplifying device according to the present invention described above with reference to FIG. 1, between the semi-insulating substrate 11 and the third semiconductor layer 14,
Except that a high-resistance semiconductor layer 51 made of, for example, InAlAs is interposed, it has a configuration similar to that of the semiconductor light receiving / amplifying device described above with reference to FIG. The semiconductor light-receiving / amplifying device according to the present invention having such a configuration has the same structure as the semiconductor light-receiving / amplifying device according to the present invention described above with reference to FIG. 1 except for the matters described above. Although the description is omitted, the same excellent operational effects as those of the semiconductor light receiving / amplifying device according to the present invention described above with reference to FIG.
For 51, the third semiconductor layer 14 thereabove, especially the first semiconductor layer 12 as an active layer of the PN junction field effect transistor, has a better crystal than in the case where the high resistance semiconductor layer 15 is not provided. The PN junction field effect transistor can be operated with better characteristics than the semiconductor light receiving / amplifying device according to the present invention shown in FIG. Third Embodiment Next, a third embodiment of the semiconductor light receiving / amplifying device according to the present invention will be described with reference to FIG. 4, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. The semiconductor light receiving / amplifying device according to the present invention shown in FIG.
In the semiconductor light receiving / amplifying device according to the present invention described above with reference to FIG. 1, the semi-insulating substrate 11 has a recess 60, and accordingly the third semiconductor layer 14 has a recess 61, and the recess Place 61
The sixth semiconductor layer 17 is formed in the recess 61 of the third semiconductor layer 14.
The semiconductor light receiving / amplifying device according to the present invention has the same structure as that of the semiconductor light receiving / amplifying device according to the present invention described above with reference to FIG. The semiconductor light-receiving / amplifying device according to the present invention having such a configuration has the same structure as the semiconductor light-receiving / amplifying device according to the present invention described above with reference to FIG. 1 except for the matters described above. Although not described, the same advantageous effects as in the case of the semiconductor light receiving / amplifying device according to the present invention described above with reference to FIG. 1 can be obtained, and the electrode 42 can be formed without fear of disconnection. [Fourth Embodiment] Next, referring to FIG.
A fourth embodiment of the amplification device will be described. 5, parts corresponding to those in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted. The semiconductor light receiving / amplifying device according to the present invention shown in FIG.
In the semiconductor light receiving / amplifying device according to the present invention described above with reference to FIG. 4, as in the case of the semiconductor light receiving / amplifying device according to the present invention shown in FIG. 3, the semi-insulating substrate 11 and the third semiconductor layer 14 are used.
It has the same structure as that of the semiconductor light receiving / amplifying device according to the present invention described above with reference to FIG. According to the configuration of the semiconductor light receiving / amplifying device of the present invention having such a configuration, although the detailed description is omitted, the excellent operational effects described above with reference to FIGS. 4 and 2 can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing a first embodiment of a semiconductor light receiving / amplifying device according to the present invention. FIG. 2 is a schematic cross-sectional view in the sequential steps showing the manufacturing method. FIG. 3 is a schematic sectional view showing a second embodiment of the semiconductor light receiving / amplifying device according to the present invention. FIG. 4 is a schematic sectional view showing a third embodiment of the semiconductor light receiving / amplifying device according to the present invention. FIG. 5 is a schematic sectional view showing a fourth embodiment of the semiconductor light receiving / amplifying device according to the present invention. FIG. 6 is a schematic cross-sectional view showing a conventional semiconductor light receiving / amplifying device. 1 ... Semi-insulating semiconductor substrate 2 ... Semiconductor layers 3, 4 ... Semiconductor regions 5, 6, 7, 8, 10 ... Window 9 ... Surface-protecting insulating film 11 ... Semi-insulating semiconductor substrate 12, 13, 14, 15, 16, 17 ... semiconductor layers 21, 22 ... semiconductor regions 31, 32, 33, 36 ... windows 35 ... insulating films 41, 42, 43, 44 for surface protection ... electrodes 51 ... ... High resistance semiconductor layer

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Shingo Uehara               3-1 Morinosato Wakamiya, Atsugi Nippon Telegraph and Telephone               Atsugi Electric Communication Laboratory Co., Ltd.                (56) References JP-A-58-56364 (JP, A)                 JP-A-60-211972 (JP, A)                 JP-A-60-164355 (JP, A)

Claims (1)

(57) [Claims] On a semi-insulating semiconductor substrate made of InP, an n-type first InGaAs-based semiconductor layer and an n-type InP
And a second semiconductor layer formed by laminating a third semiconductor layer in that order, and a fourth semiconductor having an n-type and an InGaAs system is formed on the third semiconductor layer. A sixth semiconductor layer in which a layer and a fifth semiconductor layer having an n-type and made of InP are laminated in that order, and in the third semiconductor layer, the semi-insulating substrate side and From the opposite side, a first semiconductor region having p-type is formed,
A PN junction field effect transistor having the first semiconductor layer as an active layer is configured, and a second p-type transistor is formed in the sixth semiconductor layer from a side opposite to the third semiconductor layer side. A semiconductor light-receiving device characterized in that a semiconductor region is formed to constitute a photodiode which can be regarded as a PIN junction type in which the fourth semiconductor layer serves as a light absorption layer and the third semiconductor layer serves as an electrode layer.
Amplification device.