Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
1999-03-09
2001-06-26
Lee, Eddie C. (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S184000, C257S431000, C438S057000, C438S073000
Reexamination Certificate
active
06252286
ABSTRACT:
RELATED APPLICATION DATA
The present application claims priority to Japanese Application No. P10-067145 filed Mar. 17, 1998 which application is incorporated herein by reference to the extent permitted by law.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device having a light-receiving element, an optical pickup device and a method of manufacturing a semiconductor device having a light-receiving element.
2. Description of the Related Art
Photodiodes available as a light-receiving element capable of converting a light signal into an electrical signal are widely used as a control light sensor in a variety of photoelectric converters, e.g. a sensor for detecting an information signal (hereinafter referred to as an RF signal), a tracking error signal, a focusing error signal or the like in a so-called optical pickup device for optically recording or reproducing or for effecting both of optical recording and reproduction on an optical recording medium.
This light-receiving element is mounted on the same semiconductor substrate in a mixed state together with other circuit elements, e.g. a variety of circuit elements such as a bipolar transistor, a resistor, a capacitor or the like, thereby being configured as a so-called photo-IC (optical integrated circuit). Such photo-IC is generally manufactured in accordance with a manufacturing method of a bipolar transistor serving as the above-mentioned other circuit elements.
In a photo-IC having a high-speed and high-sensitivity light-receiving element, there is proposed such one having a high-resistance epitaxial semiconductor layer.
FIG. 1
is a schematic cross-sectional view of a conventional this kind of a photo-IC in which a photodiode PD serving as a light-receiving element and a bipolar transistor TR are mounted in a mixed state. In this example, there is configured a bipolar transistor available as a photo-IC in which an npn-type transistor TR and an anode-common type photodiode PD are formed on the same semiconductor substrate
1
.
In this bipolar IC, a high impurity concentration p-type buried layer
3
is formed on the whole surface of one major surface of a p-type Si semiconductor base
2
, and a low impurity concentration p-type first semiconductor layer
31
comprising an anode region
4
of the photodiode PD is epitaxially grown on this buried layer
3
. Then, a high impurity concentration collector buried region
5
is formed on this first semiconductor layer
31
at its portion in which the transistor TR is formed. A high impurity concentration buried separating region
6
is selectively deposited between respective circuit elements and on the separating portion of the photodiode PD, which will be described later on, etc. Also, at the same time this buried separating region
6
is deposited, a p-type high impurity concentration buried region
8
is formed under a contact portion of an anode electrode
7
relative to the photodiode PD.
On the first semiconductor layer
31
, there is further epitaxially deposited a low impurity concentration n-type second semiconductor layer
32
forming a cathode region
9
of the photodiode PD and a collector region
10
of the transistor TR.
On the surface of the Si semiconductor substrate
1
in which the first and second semiconductor layers
31
and
32
are epitaxially deposited on the semiconductor base
2
, i.e. the second semiconductor layer
32
, there is deposited a separating and insulating layer
11
made of SiO
2
between electrically-separated semiconductor circuit elements or regions by a local heat oxidation, i.e. so-called LOCOS (Local Oxidation of Silicon).
A p-type high impurity concentration separating region
12
is formed between the separating and insulating layer
11
at the insulating and separating portion formed between the circuit elements below the separating and insulating layer
11
and the buried separating region
6
formed below the separating and insulating layer. A high impurity concentration p-type anode electrode deriving region
13
is deposited on the high impurity concentration buried layer
8
, and a high impurity concentration anode contact region
14
is deposited on the anode electrode deriving region. A p-type high impurity concentration separating region
30
is deposited on the buried region
6
formed on the separated portion of the anode region
4
in contact with this region
6
.
Then, an n-type high impurity concentration collector electrode deriving region
15
and a p-type base region
16
are deposited on the collector region
10
. An n-type emitter region
17
is deposited on the base region
16
.
Also, on each anode
4
of the photodiode PD, there is deposited a high impurity concentration cathode region
18
to which a cathode electrode
19
is contacted in an ohmic fashion.
On the surface of the semiconductor substrate
1
, there is deposited an insulating layer
21
made of such as SiO2 or the like. This insulating layer has formed therethrough electrode contact-windows to which the emitter, the base and the collector electrodes
20
E,
20
B and
20
C of the transistor TR are contacted, respectively. Then, on the insulating layer, there is deposited an interlayer insulator layer
22
such as SiO
2
or the like. This interlayer insulator layer has formed thereon a light-shielding layer
23
made of Al or the like and having a light-receiving window. A protecting film
24
is deposited on this light-shielding layer.
Then, the insulating layers
21
and
22
are used as antireflection films so that a detection light is irradiated on the photodiode PD through the light-receiving window of the light-shielding layer
23
.
The photodiode PD in the above-mentioned IC may be arranged as a sensor for detecting an RF signal, a tracking error signal and a focus error signal in an optical pickup device which is able to optically record, reproduce or both record and reproduce an optical recording medium, for example.
FIG. 2A
shows a plan pattern view of the photodiode PD available as the sensor for detecting the RF signal, the tracking error signal and the focus error signal in the optical pickup device, for example. In this example, three light spots of a center light spot SP
0
and side spots SP
S1
and SP
S2
on both sides from an optical recording medium, e.g. optical disk are irradiated on a quadrant photodiode PD
0,
for example, and photodiodes PD
S1
and PD
S2
on both sides, whereby the focus error signal is obtained by a calculation of (A+C)−(B+D) where A to D respectively represent outputs photo-electrically-converted at respective portions A, B, C and D of the quadrant photodiode PD, the tracking error signal is obtained by a calculation of (E−F) where E and F respectively represent the outputs of other two photodiodes PD
S1
and PD
S2
and the signal read-out output, i.e. RF signal is obtained by a calculation of (A+B+C+D).
FIG. 2B
similarly shows an example of the photodiode PD which is applied to an optical pickup device, for example. In this example, spots SP
1
and SP
2
are irradiated on the photodiodes PD
1
and PD
2
which are respectively parallelly divided by four to provide photodiode portions A, B, C, D and A′, B′, C′, D′. In this case, the two photodiode portions B, C and B′, C′ at the center of the respective photodiodes are formed as extremely-narrow stripe-like patterns of 14 (m pitch, for example. Then, when outputs of the respective portions A, B, C, D and A′, B′, C′, D′ of the respective photodiodes PD
1
and PD
2
are respectively assumed to be A, B, C, D and A′, B′, C′, D′, a focus error signal is obtained by a calculation of (B+C)−(A+D)−{(B′+C′)−(A′+D′)}, then a tracking error signal is obtained by a calculation of (A+B+C′+D′)−(C+D+A′+B′) and an RF signal is obtained by a calculation of (A+B+C&
Lee Eddie C.
Sonnenschein Nath & Rosenthal
Sony Corporation
Wilson Allan R.
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