Silicon controlled rectifier device and preparation method thereof
阅读说明:本技术 一种可控硅器件及其制备方法 (Silicon controlled rectifier device and preparation method thereof ) 是由 张潘德 赖首雄 蓝浩涛 于 2019-09-09 设计创作,主要内容包括:本发明属于半导体器件技术领域,提供了一种可控硅器件及其制备方法,通过将衬底层第一侧的正面阳极层以及衬底层第二侧的背面阳极层设置成“凸”形,且正面阳极层的凸起部位于所述正面阳极层的基部与所述衬底层之间,背面阳极层的凸起部位于所述背面阳极层的基部与所述衬底层之间,使得正面隔离层与所述正面阳极层的凸起部之间设有正面衬底隔离区,背面隔离层与所述背面阳极层的凸起部之间设有背面衬底隔离区,从而可以通过调节正面衬底隔离区和背面衬底隔离区的宽度对可控硅器件的击穿电压进行调节,避免了在制备过程中需要针对击穿电压的不同更换不同的硅基材,导致的制造成本增加、工艺复杂等问题。(The invention belongs to the technical field of semiconductor devices and provides a silicon controlled device and a preparation method thereof, wherein a front anode layer at the first side of a substrate layer and a back anode layer at the second side of the substrate layer are arranged in a convex shape, a protruding part of the front anode layer is positioned between a base part of the front anode layer and the substrate layer, and a protruding part of the back anode layer is positioned between the base part of the back anode layer and the substrate layer, so that a front substrate isolation region is arranged between the front isolation layer and the protruding part of the front anode layer, and a back substrate isolation region is arranged between the back isolation layer and the protruding part of the back anode layer, therefore, the breakdown voltage of the silicon controlled device can be adjusted by adjusting the widths of the front substrate isolation region and the back substrate isolation region, thereby avoiding the need of replacing different silicon substrates aiming at different, resulting in problems of increased manufacturing cost, complicated process, etc.)
1. A silicon controlled device, comprising: a substrate layer having a first conductivity type;
the positive anode layer is arranged on the first side of the substrate layer and has a second conduction type, the positive anode layer is in a convex structure, and a convex part of the positive anode layer is positioned between the base of the positive anode layer and the substrate layer;
the back anode layer is arranged on the second side of the substrate layer and has a second conductive type, the back anode layer is of a convex structure, a protruding part of the back anode layer is positioned between the base of the back anode layer and the substrate layer, and the second side of the substrate layer is opposite to the first side of the substrate layer;
a front side isolation layer arranged on the first side of the substrate layer, contacting the substrate layer, and dividing the front side anode layer into an effective front side anode layer and an ineffective front side anode layer; the depth of the front surface isolation layer is greater than the thickness of the front surface anode layer, and a front surface substrate isolation region is arranged between the front surface isolation layer and the protruding part of the front surface anode layer;
a back isolation layer disposed on a second side of the substrate layer, contacting the substrate layer, and dividing the back anode layer into an active back anode layer and an inactive back anode layer; the depth of the back isolating layer is greater than the thickness of the back anode layer, and a back substrate isolating region is arranged between the back isolating layer and the protruding part of the back anode layer;
a plurality of front side metal layers disposed on the active front side anode layer;
a plurality of front cathode regions disposed between the active front anode layer and the front metal layer and having a first conductivity type;
a back side metal layer disposed on the active back side anode layer; and
a back cathode region disposed between the active back anode layer and the back metal layer and having a first conductivity type.
2. The silicon controlled device as claimed in claim 1, wherein the first conductivity type is N-type and the second conductivity type is P-type.
3. The silicon controlled device of claim 1, wherein the thickness of the base of the front side anode layer is 10-30 um.
4. The silicon controlled device of claim 1, wherein the thickness of the raised portion of the front anode layer is 25-35 um.
5. The silicon controlled device of claim 1, wherein the front side substrate isolation region has a width of 1-15 um.
6. A preparation method of a silicon controlled rectifier device is characterized by comprising the following steps:
step a: determining an anode region on a first side and a second side opposite to the first side of a substrate layer with a first conductivity type by using a first mask layer, and forming a first oxide layer and a second oxide layer with a masking effect by means of thermal oxidation;
step b: implanting second conductivity type impurity ions into a substrate layer by means of ion implantation under the masking of the first oxide layer and the second oxide layer to form a front anode layer on a first side of the substrate layer and a back anode layer on a second side of the substrate layer;
step c: removing the first oxide layer and the second oxide layer, and implanting second conductive type impurity ions into the substrate layer in an ion implantation manner so as to enable the front anode layer and the back anode layer to be in a convex shape;
step d: determining a plurality of front cathode regions on the front anode layer by using a second mask layer, determining a back cathode region on the back anode layer by using a third mask layer, implanting first conductive type impurity ions into the front cathode regions under the masking of the second mask layer to form a plurality of front cathode regions, and implanting first conductive type impurity ions into the back cathode regions under the masking of the third mask layer to form a back cathode region;
step e: removing the second mask layer and the third mask layer, determining a front isolation layer area on the front anode layer by adopting a fourth mask layer, and etching under the masking of the fourth mask layer to form a front isolation groove, wherein the depth of the front isolation groove is greater than the thickness of the front anode layer so as to divide the front anode layer into an effective front anode layer and an ineffective front anode layer, and a front substrate isolation area is arranged between a protruding part of the front anode layer and the front isolation groove; etching the back anode layer to form a back isolation groove in the same way so as to divide the back anode layer into an effective back anode layer and an ineffective back anode layer, and arranging a back substrate isolation region between a protruding part of the back anode layer and the back isolation groove;
step f: filling an insulating material in the front isolation groove to form a front isolation layer, and filling an insulating material in the back isolation groove to form a back isolation layer;
step g: and forming a plurality of front metal layers on the surfaces of the front cathode regions and the effective front anode layer, wherein the front metal layers are not contacted with each other, forming a back metal layer on the surface of the effective back anode layer, and the back cathode region is positioned between the back metal layer and the effective back anode layer.
7. The method of claim 6, wherein step a comprises: and determining a front anode area on the first side of the substrate layer with the first conductivity type by using a first mask layer, and forming a first oxidation layer with the thickness of 1-5um in a thermal oxidation mode.
8. The method of claim 6, wherein step b comprises: implanting a boron source into the first side of the substrate layer at a temperature of 1200-1250 degrees celsius under the masking of the first oxide layer to form a front side anode layer.
9. The method of claim 6, wherein step c comprises: and removing the first oxide layer, and injecting a boron source into the first side of the substrate layer at the temperature of 1200-1500 ℃ so that the first side of the substrate layer is covered by the front anode layer, wherein the front anode layer has various thicknesses.
10. The method of claim 6, wherein step f comprises: and filling an insulating material in the front isolation groove in a glass coating mode.
Technical Field
The invention relates to the technical field of semiconductor devices, in particular to a silicon controlled rectifier device and a preparation method thereof.
Background
A Silicon Controlled Rectifier (SCR) is a high-power electrical component, also called a thyristor, and has the advantages of small size, high efficiency, long service life, and the like, and is mainly applied to low-frequency switching, for example, 50 or 60Hz power switching. The rated voltage of the thyristor is usually the smaller value of forward voltage or reverse voltage, and if transient overvoltage occurs in the circuit, the thyristor can be triggered or damaged, so the rated voltage is usually set to be 2-3 times of the working peak value.
However, since the breakdown voltage of the thyristor is generally determined by the concentration of the silicon substrate, if the breakdown voltage needs to be changed, the silicon substrate needs to be replaced, which leads to problems of increased manufacturing cost, complicated process, and the like.
Disclosure of Invention
The invention aims to provide a silicon controlled rectifier device and a preparation method thereof, aiming at improving the breakdown voltage of the silicon controlled rectifier on the premise of not changing a silicon substrate.
The invention provides a silicon controlled device, comprising: a substrate layer having a first conductivity type;
the positive anode layer is arranged on the first side of the substrate layer and has a second conduction type, the positive anode layer is in a convex structure, and a convex part of the positive anode layer is positioned between the base of the positive anode layer and the substrate layer;
the back anode layer is arranged on the second side of the substrate layer and has a second conductive type, the back anode layer is of a convex structure, a protruding part of the back anode layer is positioned between the base of the back anode layer and the substrate layer, and the second side of the substrate layer is opposite to the first side of the substrate layer;
a front side isolation layer arranged on the first side of the substrate layer, contacting the substrate layer, and dividing the front side anode layer into an effective front side anode layer and an ineffective front side anode layer; the depth of the front surface isolation layer is greater than the thickness of the front surface anode layer, and a front surface substrate isolation region is arranged between the front surface isolation layer and the protruding part of the front surface anode layer;
a back isolation layer disposed on a second side of the substrate layer, contacting the substrate layer, and dividing the back anode layer into an active back anode layer and an inactive back anode layer; the depth of the back isolating layer is greater than the thickness of the back anode layer, and a back substrate isolating region is arranged between the back isolating layer and the protruding part of the back anode layer;
a plurality of front side metal layers disposed on the active front side anode layer;
a plurality of front cathode regions disposed between the active front anode layer and the front metal layer and having a first conductivity type;
a back side metal layer disposed on the active back side anode layer; and
a back cathode region disposed between the active back anode layer and the back metal layer and having a first conductivity type.
Optionally, the first conductivity type is an N type, and the second conductivity type is a P type.
Optionally, the thickness of the base of the front anode layer is 10-30 um.
Optionally, the thickness of the protruding portion of the front anode layer is 25-35 um.
Optionally, the width of the front substrate isolation region is 1-15 um.
The embodiment of the application also provides a preparation method of the silicon controlled device, which comprises the following steps:
step a: determining an anode region on a first side and a second side opposite to the first side of a substrate layer with a first conductivity type by using a first mask layer, and forming a first oxide layer and a second oxide layer with a masking effect by means of thermal oxidation;
step b: implanting second conductivity type impurity ions into a substrate layer by means of ion implantation under the masking of the first oxide layer and the second oxide layer to form a front anode layer on a first side of the substrate layer and a back anode layer on a second side of the substrate layer;
step c: removing the first oxide layer and the second oxide layer, and implanting second conductive type impurity ions into the substrate layer in an ion implantation manner so as to enable the front anode layer and the back anode layer to be in a convex shape;
step d: determining a plurality of front cathode regions on the front anode layer by using a second mask layer, determining a back cathode region on the back anode layer by using a third mask layer, implanting first conductive type impurity ions into the front cathode regions under the masking of the second mask layer to form a plurality of front cathode regions, and implanting first conductive type impurity ions into the back cathode regions under the masking of the third mask layer to form a back cathode region;
step e: removing the second mask layer and the third mask layer, determining a front isolation layer area on the front anode layer by adopting a fourth mask layer, and etching under the masking of the fourth mask layer to form a front isolation groove, wherein the depth of the front isolation groove is greater than the thickness of the front anode layer so as to divide the front anode layer into an effective front anode layer and an ineffective front anode layer, and a front substrate isolation area is arranged between a protruding part of the front anode layer and the front isolation groove; etching the back anode layer to form a back isolation groove in the same way so as to divide the back anode layer into an effective back anode layer and an ineffective back anode layer, and arranging a back substrate isolation region between a protruding part of the back anode layer and the back isolation groove;
step f: filling an insulating material in the front isolation groove to form a front isolation layer, and filling an insulating material in the back isolation groove to form a back isolation layer;
step g: and forming a plurality of front metal layers on the surfaces of the front cathode regions and the effective front anode layer, wherein the front metal layers are not contacted with each other, forming a back metal layer on the surface of the effective back anode layer, and the back cathode region is positioned between the back metal layer and the effective back anode layer.
Optionally, the step a includes: and determining a front anode area on the first side of the substrate layer with the first conductivity type by using a first mask layer, and forming a first oxidation layer with the thickness of 1-5um in a thermal oxidation mode.
Optionally, step b includes: implanting a boron source into the first side of the substrate layer at a temperature of 1200-1250 degrees celsius under the masking of the first oxide layer to form a front side anode layer.
Optionally, step c includes: and removing the first oxide layer, and injecting a boron source into the first side of the substrate layer at the temperature of 1200-1500 ℃ so that the first side of the substrate layer is covered by the front anode layer, wherein the front anode layer has various thicknesses.
Optionally, step f includes: and filling an insulating material in the front isolation groove in a glass coating mode.
In the silicon controlled device and the preparation method thereof provided by the invention, the front anode layer at the first side of the substrate layer and the back anode layer at the second side of the substrate layer are arranged in a convex shape, the protruding part of the front anode layer is positioned between the base part of the front anode layer and the substrate layer, and the protruding part of the back anode layer is positioned between the base part of the back anode layer and the substrate layer, so that a front substrate isolation region is arranged between the front isolation layer and the protruding part of the front anode layer, and a back substrate isolation region is arranged between the back isolation layer and the protruding part of the back anode layer, therefore, the breakdown voltage of the silicon controlled device can be adjusted by adjusting the width of the front substrate isolation region and the back substrate isolation region, and the increase of the manufacturing cost, the increase of the manufacturing cost and the like caused by, The process is complex and the like.
Drawings
Fig. 1 is a schematic cross-sectional structural diagram of a thyristor device according to an embodiment of the present application;
fig. 2 is a schematic cross-sectional view of a thyristor device provided in an embodiment of the present application at the
fig. 3 is a schematic cross-sectional view of a thyristor device provided in an embodiment of the present application at a protruding
fig. 4 is a parameter diagram of a thyristor device according to an embodiment of the present application;
FIG. 5 is a graph of breakdown voltage versus device parameter obtained from simulation;
FIG. 6 is another graph of simulated breakdown voltage versus device parameter;
fig. 7 is a schematic structural diagram of a
fig. 8 is a schematic structural diagram of a
fig. 9 is another schematic structural diagram after forming a
fig. 10 is a schematic structural diagram of a
fig. 11 is a schematic structural diagram of a method for manufacturing a semiconductor device according to an embodiment of the present disclosure after forming a front
fig. 12 is a schematic structural diagram of a front-
fig. 13 is a schematic structural diagram of a plurality of front-
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
Generally, the breakdown voltage of a silicon controlled rectifier is determined by the doping concentration of a substrate layer, silicon substrates with different doping concentrations are adopted as the substrate layer according to different breakdown voltages, the higher the doping concentration of the silicon substrate is, the lower the breakdown voltage of the prepared silicon controlled rectifier is, if the breakdown voltage of the silicon controlled rectifier needs to be increased, the silicon substrate with the lower doping concentration is generally required to be replaced as the substrate layer, and the like, so that the problems of cost increase, complex process and the like are caused by generally adjusting original process parameters when the silicon substrate is replaced, in order to increase the breakdown voltage of the silicon controlled rectifier under the premise of not changing the concentration of the silicon substrate, the embodiment of the application provides a novel silicon controlled rectifier device, and aims to improve the breakdown voltage of the silicon controlled rectifier and increase the safety factor in design under the original process parameters, without affecting the functional characteristics of the silicon controlled rectifier.
Fig. 1 is a schematic structural diagram of a thyristor device according to an embodiment of the present application, and referring to fig. 1, the thyristor device in the embodiment includes: a
In this embodiment, the first side of the
Fig. 2 is a schematic cross-sectional view at the
Further, fig. 3 is a schematic cross-sectional view of the protruding
In one embodiment, referring to fig. 4, the width of the front
In one embodiment, fig. 6 is another graph of the breakdown voltage and the device parameter obtained by simulation, and referring to fig. 6, when the thickness Y of the protruding
In one embodiment, the parameters of the back anode layer on the second side of the
In one embodiment, the first conductivity type is N-type and the second conductivity type is P-type. In the present embodiment, the first conductivity type is N-type, i.e., the semiconductor material is made to be an electron conductivity type semiconductor by doping the semiconductor material with impurity ions of N-type conductivity, and the second conductivity type is P-type, i.e., the semiconductor material is made to be a hole conductivity type semiconductor by doping the semiconductor material with impurity ions of P-type conductivity, wherein the impurity ions of N-type conductivity are N-type impurity ions such as arsenic ions, phosphorus ions, nitrogen ions, and the like, and the impurity ions of P-type conductivity are P-type impurity ions such as boron ions.
In one embodiment, the thickness Z of the
In one embodiment, the thickness Y of the
In one embodiment, the width X of the front substrate isolation region is 1-15 um. In the present embodiment, when the width X of the front substrate isolation region is 1 to 15um, a higher breakdown voltage can be obtained.
In one embodiment, the front
In one embodiment, the insulating material is silicon dioxide. In this embodiment, the
In one embodiment, the thickness of the
In one embodiment, the front metal layer is metallic aluminum.
In one embodiment, the back metal layer is metallic silver.
An embodiment of the present application further provides a method for manufacturing a silicon controlled device, where the method includes:
step a: the anode region is defined by a first mask layer on a first side and on a second side opposite to the first side of the
In this embodiment, the first mask layer is used to define a front anode region on the first side of the
In one embodiment, the
In one embodiment, the step a includes: a front anode area is defined on a first side of a
Step b: a second conductivity type impurity is ion implanted into the
In this embodiment, the first mask layer is removed, and then a
In one embodiment, the step b comprises: a boron source is implanted into the first side of the
In one embodiment, the thickness of the front
Step c: the
In this embodiment, after implanting the second conductive type impurity ions into the
In one embodiment, the step c comprises: and removing the first oxide layer, and injecting a boron source into the first side of the substrate layer at the temperature of 1200-1500 ℃ so that the first side of the
In one embodiment, the implantation depth of the boron source is 10-30um in this embodiment, so that two times of implantation of the boron source form a PN junction structure with high and low drop.
In this embodiment, the
Step d: a plurality of front cathode regions are defined on the
In the present embodiment, different cathode regions can be formed on both sides of the
In one embodiment, step d in this embodiment specifically includes: the
Step e: removing the second mask layer and the third mask layer, determining a front surface isolation layer region on the front
In this embodiment, a fourth mask layer is used to determine a front isolation layer region on the
Step f: the
In one embodiment, the step f comprises: and filling an insulating material in the
In one embodiment, the insulating material is silicon dioxide, and the
Step g: a plurality of front metal layers 51 are formed on the
In the silicon controlled device and the preparation method thereof provided by the invention, the front anode layer at the first side of the substrate layer and the back anode layer at the second side of the substrate layer are arranged in a convex shape, the protruding part of the front anode layer is positioned between the base part of the front anode layer and the substrate layer, and the protruding part of the back anode layer is positioned between the base part of the back anode layer and the substrate layer, so that a front substrate isolation region is arranged between the front isolation layer and the protruding part of the front anode layer, and a back substrate isolation region is arranged between the back isolation layer and the protruding part of the back anode layer, therefore, the breakdown voltage of the silicon controlled device can be adjusted by adjusting the width of the front substrate isolation region and the back substrate isolation region, and the increase of the manufacturing cost, the increase of the manufacturing cost and the like caused by, The process is complex and the like.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
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