CN102376813A - Uncooled infrared detector device and manufacturing method thereof - Google Patents

Abstract

The invention provides an uncooled infrared detector device and a manufacturing method thereof. The uncooled infrared detector device comprises a substrate and a SiGe layer arranged on the substrate, wherein the substrate comprises an insulating layer, and the SiGe layer comprises a P-type area and an N-type area which are adjacent to each other. Correspondingly, the invention further provides another uncooled infrared detector device which comprises an SOI (Silicon on Insulator) substrate and a P-type SiGe layer, wherein the SOI substrate has an N-type top silicon layer; the P-type SiGe layer is arranged on the N-type top silicon layer; and the P-type SiGe layer is selectively epitaxial grown. In the uncooled infrared detector device, the P-type area of a diode is made of a SiGe material, thereby forming a SiGe PN junction diode or SiGe/Si heterojunction diode so as to reduce a working voltage. A forbidden bandwidth of the SiGe material changes within a range of 0.66-1.12eV following the change of Ge components. Relative to a monocrystalline silicon diode, the forbidden bandwidth of the SiGe material is narrower, thereby being easier to stimulate the forming of the PN junction diode and promoting a voltage temperature response coefficient.

Description

Non-refrigerated infrared detector spare and preparation method thereof

Technical field

The present invention relates to the infrared detection technique field, particularly a kind of non-refrigerated infrared detector spare and preparation method thereof.

Background technology

Infrared detector is the core parts of thermal imaging system; Mainly be divided into two types: refrigeration mode (based on photon detection) and non-refrigeration type (based on hot-probing); The former once was considered to infra-red heat Detection Techniques best in the practical application; But owing to need the coupling refrigerating plant, its manufacturing cost and use cost is higher.

Non-refrigerated infrared detector spare has obtained tremendous development in recent years, compares with refrigerated infrared detector spare, and non-refrigerated infrared detector spare need not installed refrigerating plant in thermal imaging system, so size is less, weight is light and power consumption is lower; In addition, wideer spectral response and longer operating time also can be provided.

According to the infrared spectrum coverage, infrared detector also is divided into short-wave infrared type, medium wave infrared type and LONG WAVE INFRARED type (also claim far infrared, cover 5～14 μ m).In the existing non-refrigeration Long Wave Infrared Probe spare, mainly contain two types: a kind of is with VOx, amorphous silicon or amorphous Si _xGe _1-xAs the infrared detector of thermo-sensitive resistor, it obtains infrared image information through the output signal that detects thermo-sensitive resistor; Another kind is with the infrared detector of monocrystal silicon PN junction diode as sensing unit; Its through the output signal that detects diode obtain infrared image information (referring to Masashi Ueno et al; " 640X480 pixel uncooled infrared FPA with SOI diode detectors "; Proc.Of SPIE Vol.5783,2005, PP566).

The voltage temperature response coefficient is the important parameter of the temperature control of decision non-refrigerated infrared detector; At present; In the monocrystal silicon PN junction diode-type Infrared Detectors, the forward voltage temperature response coefficient of diode is about 1.3mV/K, and is little to the influence of the forward voltage temperature response coefficient of diode through each item technological parameter that changes single diode; Usually need a plurality of diodes of series connection (for example 6-8) could improve the whole temperature control of Infrared Detectors; Could satisfy the demand of practical application, yet the operating voltage that a plurality of diode in series will cause monocrystal silicon PN junction diode-type Infrared Detectors is big (usually above 6V).

Summary of the invention

The problem that the present invention solves provides non-refrigerated infrared detector spare that a kind of temperature control is higher, operating voltage is lower and preparation method thereof.

For addressing the above problem, the present invention provides a kind of non-refrigerated infrared detector spare, comprising:

The substrate that includes insulating barrier;

Si on the said substrate _xGe _1-xLayer, said Si _xGe _1-xComprise adjacent p type island region and N type district in the layer.

Wherein, said substrate is the SOI substrate.

Optional, said substrate comprises the buried regions oxide layer on monocrystalline silicon layer and the said monocrystalline silicon layer, said insulating barrier is the buried regions oxide layer.

Said Si _xGe _1-xLayer according to the variation energy gap of Ge component in the scope of 0.66-1.12eV.

Accordingly, a kind of manufacture method of non-refrigerated infrared detector spare is provided also, comprises:

Substrate is provided;

On said substrate, form Si _xGe _1-xLayer;

At said Si _xGe _1-xForm adjacent p type island region and N type district in the layer.

Optional, when said substrate is the SOI substrate, on said substrate, form Si _xGe _1-xLayer adopts epitaxial growth technology.

Optional, when said substrate is monocrystalline substrate, on said substrate, forms the SiGe layer and adopt epitaxial growth technology, also comprise then: be infused in monocrystalline substrate and Si through ion _xGe _1-xThe buried regions of the formation at the interface oxide layer of layer.

Optional, when said substrate is monocrystalline substrate, on said substrate, form Si _xGe _1-xLayer adopts Si _xGe _1-xBody material and monocrystalline substrate bonding are made.

Accordingly, a kind of non-refrigerated infrared detector spare is provided also, comprises:

SOI substrate, said SOI substrate have N type top silicon layer;

P type Si on the silicon layer of said N type top _xGe _1-xLayer, said P type Si _xGe _1-xLayer adopts selective epitaxial growth.

Accordingly, a kind of manufacture method of non-refrigerated infrared detector spare comprises:

SOI is provided substrate, and said SOI substrate has N type top silicon layer;

On the silicon layer of said N type top, form oxide layer;

Remove the said oxide layer of part and expose following monocrystalline silicon layer;

The top silicon surface epitaxial growth P type Si that is exposing _xGe _1-xLayer.

Compared with prior art, technique scheme has the following advantages:

The present invention adopts Si _xGe _1-xMaterial is made the p type island region of diode, forms SiGe PN junction diode or SiGe/Si heterojunction diode and reduces operating voltage, because Si _xGe _1-xMaterial changes between 0.66-1.12eV according to its energy gap of change of component of Ge, for the monocrystalline silicon diode, and Si _xGe _1-xThe energy gap of material is narrower, forms the PN junction diode thus and excites more easily, can reduce (qVf-Eg) item, thereby improves the voltage temperature response coefficient.

Through simulation, adopt the cut-in voltage of the diode of SiGe p type island region to be about the half the of monocrystalline silicon diode, and its voltage temperature response coefficient can improve 10% approximately, therefore can obtain high voltage temperature response coefficient and reduce operating voltage.

Description of drawings

Shown in accompanying drawing, above-mentioned and other purpose, characteristic and advantage of the present invention will be more clear.Reference numeral identical in whole accompanying drawings is indicated identical part.Painstakingly do not draw accompanying drawing, focus on illustrating purport of the present invention by actual size equal proportion convergent-divergent.

Fig. 1 is the structural representation of non-refrigerated infrared detector spare among the embodiment one;

Fig. 2 can be with comparison diagram for SiGe PN junction among the embodiment one and traditional monocrystal silicon PN junction;

Fig. 3 is the structural representation of non-refrigerated infrared detector spare among the embodiment two;

Fig. 4 is the structural representation of non-refrigerated infrared detector spare among the embodiment three;

Fig. 5 can be with comparison diagram for SiGe/Si heterojunction among the embodiment three and traditional monocrystal silicon PN junction;

Fig. 6 is the I-V curvilinear mold graphoid of SiGe PN junction and traditional monocrystal silicon PN junction in the embodiment of the invention.

Embodiment

For make above-mentioned purpose of the present invention, feature and advantage can be more obviously understandable, does detailed explanation below in conjunction with the accompanying drawing specific embodiments of the invention.

A lot of details have been set forth in the following description so that make much of the present invention; But the present invention can also adopt other to be different from alternate manner described here and implement; Those skilled in the art can do similar popularization under the situation of intension of the present invention, so the present invention does not receive the restriction of following disclosed specific embodiment.

Secondly, the present invention combines sketch map to be described in detail, when the embodiment of the invention is detailed; For ease of explanation; The profile of expression device architecture can be disobeyed general ratio and done local the amplification, and said sketch map is example, and it should not limit the scope of the present invention's protection at this.The three dimensions size that in actual fabrication, should comprise in addition, length, width and the degree of depth.

Said as background technology part of the present invention; In the present monocrystal silicon PN junction diode-type Infrared Detectors; The forward voltage temperature response coefficient of diode is about 1.3mV/K; Each item technological parameter through changing single diode is little to the influence of the forward voltage temperature response coefficient of diode; In order to improve the whole temperature control of Infrared Detectors, a plurality of diodes of need connecting usually (for example 6-8) could satisfy the demand of practical application, yet a plurality of diode in series will cause the operating voltage of monocrystal silicon PN junction diode-type Infrared Detectors bigger.Therefore, how to improve temperature control and reduce the main direction of studying that operating voltage becomes the type infrared detector.

Inventor of the present invention adopts Si through discovering _xGe _1-xMaterial formation PN diode or SiGe/Si heterojunction diode are made non-refrigerated infrared detector spare and can well be addressed the above problem, below explanation principle of the present invention:

Formula (1) is the expression formula of diode drop temperature response coefficient.

$\frac{d{V}_f}{\mathrm{dT}}=\frac{q{V}_f-3\mathrm{kT}-E_g}{\mathrm{qT}}---\left(1\right)$

Wherein: V _f: diode drop; Q: electron charge; K: Boltzmann constant; T: diode temperature; Eg: semi-conducting material energy gap.Can find out from formula (1):

(1) reduces diode drop V _f, can improve the voltage temperature response coefficient and reduce operating voltage;

(2) through letting diode operation under suitable temperature, can improve the voltage temperature response coefficient, but, remain essentially in working and room temperature, so can not obtain higher voltage temperature response coefficient through the optimization of temperature for non-refrigerated infrared detector;

(3) reduce (qV _f-E _g) item also can improve the temperature response coefficient of voltage, because E _gRelevant with semi-conducting material itself, therefore can reduce this, thereby improve the voltage temperature sensitivity coefficient through the material of selecting other.

The voltage temperature response coefficient of traditional monocrystalline silicon diode is about 1.3mV/K; Usually the series connection of a plurality of diodes of needs guarantees the temperature control of non-refrigerated infrared detector; And the cut-in voltage of monocrystalline silicon diode is about 0.8V, so the overall operation voltage of Infrared Detectors needs 6-9V approximately, and operating voltage is higher; If in order to reduce that operating voltage reduces number of diodes then the temperature control that can reduce detector influences the use of device.Based on this, according to the analysis of formula (1), the present invention adopts Si _xGe _1-xThe PN junction diode made by material or the SiGe/Si heterojunction diode reduces operating voltage; Through theory analysis and simulation; The cut-in voltage of SiGe diode is about the half the of monocrystalline silicon diode; And its voltage temperature response coefficient can improve 10% approximately, therefore can obtain high voltage temperature response coefficient and reduce operating voltage.

Describe the specific embodiment of non-refrigerated infrared detector according to the invention and preparation method thereof in detail below in conjunction with accompanying drawing.

Embodiment one

Fig. 1 is the structural representation of non-refrigerated infrared detector spare in the present embodiment, and Fig. 2 can be with comparison diagram for SiGe PN junction in the present embodiment and traditional monocrystal silicon PN junction.

As shown in Figure 1, non-refrigerated infrared detector comprises:

SOI (Silicon On Insulator, silicon-on-insulator) substrate;

Si on the said SOI substrate _xGe _1-xLayer 104 comprises adjacent p type island region 105 and N type district 106 in the said SiGe layer 104.

Wherein, the SOI substrate is made up of end silicon layer 101, buried regions oxide layer 102 and top silicon layer 103, and silicon layer of the said end 101 is single crystal silicon material with top silicon layer 103.For infrared detector, top silicon layer 103 will approach with buried regions oxide layer 102 as far as possible, and its thickness range for example is 50nm-200nm.The SOI substrate is to form the buried regions silica through on silicon single crystal wafer, injecting oxonium ion, perhaps adopts the mode of two buik silicon material bondings to be made.

Si _xGe _1-xLayer is epitaxially grown single crystalline Si _xGe _1-xMaterial, wherein the composition of Ge can be adjusted in epitaxial process as required, and the composition of Ge is generally at 0.1-0.6 (atomic percent).P type island region 105 is formed the PN junction diode with N type district 106, and the mode that can utilize photoetching, ion to inject is made.

In semicon industry, Si _xGe _1-xMaterial is commonly used to make HBT (Heterojunction bipolar transistor, heterojunction transistor) and some high speed circuits.And mainly utilizing the SiGe material to make the responsive to temperature diode in the present embodiment, it changes the infrared radiation that receives the variations in temperature of diode into, causes that then the output voltage of diode changes the detection that realizes infrared image.

Other structures of non-refrigerated infrared detector and existing P N junction diode infrared detector structure are similar in the present embodiment.

Infrared radiation mainly is the absorption along with the diode pair infrared radiation to the influence of diode; The temperature of diode raises; Thereby cause exciting of intrinsic carrier; Under the situation of constant-current bias, can cause the variation of diode voltage, so, the power of infrared radiation just can reflect through the variation of diode voltage.And the size of semi-conducting material energy gap has determined the complexity that intrinsic carrier excites, and energy gap is narrow, causes exciting and crossing the PN junction built-in potential and build to participate in conduction of intrinsic carrier more easily, thereby improves temperature control.As shown in Figure 2, the broadband, forbidden band of monocrystalline silicon is 1.12eV, and the energy gap of Ge is 0.66eV, Si _xGe _1-xMaterial changes between 0.66-1.12eV according to its energy gap of change of component of Ge, for the monocrystalline silicon diode, and Si _xGe _1-xThe energy gap of material is narrower, forms the PN junction diode thus and excites more easily, can improve temperature control.

The manufacture method of above-mentioned non-refrigerated infrared detector spare is following:

At first, SOI is provided substrate;

Secondly, epitaxial growth Si on said SOI substrate _xGe _1-xLayer;

Then, be that mask is at said Si with the photoresist layer _xGe _1-xForm p type island region through ion implantation technology in the layer, same, be that mask is at said Si with the photoresist layer _xGe _1-xThrough ion implantation technology N type district, said N type district and p type island region are formed the PN junction diode in the layer;

Then, produce the hanging structure and the lead-in wire of sensitive detection parts again through the method for photoetching, etching, be input to peripheral reading circuit to the voltage signal of diode, this step and traditional handicraft are basic identical.

Fig. 6 is the I-V curvilinear mold graphoid of SiGe PN junction diode and traditional Si PN junction diode in the embodiment of the invention.Table 1 is the voltage temperature sensitivity table of comparisons of above-mentioned two kinds of PN junction diodes.This shows that the non-refrigerated infrared detector spare voltage temperature sensitivity in the embodiment of the invention is significantly improved, operating voltage is lower under the identical bias current.

The voltage temperature sensitivity table of comparisons of table 1 all kinds PN junction diode

N+/P-ties type	dV/dT(mV/K)
		Si-Si	1.49
Si 0.8Ge 0.2-Si 0.8Ge 0.2	1.56

Non-refrigerated infrared detector spare among the embodiment one adopts the SOI substrate, in fact also can adopt monocrystalline substrate, in following examples two, specifies.

Embodiment two

Fig. 3 is the structural representation of non-refrigerated infrared detector spare in the present embodiment, and is as shown in the figure, and said non-refrigerated infrared detector comprises:

Monocrystalline substrate 201, this monocrystalline substrate 201 has buried regions oxide layer 202;

Si on the said buried regions oxide layer 202 _xGe _1-xLayer 204, said Si _xGe _1-xComprise adjacent p type island region 205 and N type district 206 in the layer 204.

Be said Si with the difference of embodiment one _xGe _1-xLayer 204 is positioned on the buried regions oxide layer 202, rather than is positioned on the silicon layer of top.

The substrate of present embodiment is the top silicon layer not, and concrete manufacture method is: the epitaxial growth Si on said monocrystalline substrate of elder generation _xGe _1-xLayer then, is infused in monocrystalline substrate and Si through oxonium ion _xGe _1-xThe buried regions of the formation at the interface oxide layer of layer, then, the method for injecting through photoetching, etching, ion forms Si _xGe _1-xP type island region and N type district in the layer form the PN junction diode, produce the hanging structure and the lead-in wire of detector at last through the method for photoetching, etching, draw the reading circuit to the periphery to the voltage signal of diode.

In addition, the method that also can pass through bonding is Si _xGe _1-xMaterial and single crystal silicon material bonding, and form Si on the insulating barrier _xGe _1-xStructure, then carry out the making step in p type island region and N type district again.

In addition, the present invention also provides and has had Si _xGe _1-xThe non-refrigerated infrared detector of/Si heterojunction diode is specifically explained in following examples.

Embodiment three

Fig. 4 is the structural representation of non-refrigerated infrared detector spare in the present embodiment, and Fig. 5 is Si in the present embodiment _xGe _1-x/ Si heterojunction and traditional monocrystal silicon PN junction can be with comparison diagram.

As shown in Figure 4, said non-refrigerated infrared detector spare comprises:

SOI substrate, said SOI substrate have N type top silicon layer 303;

P type Si on the said N type top silicon layer 303 _xGe _1-xLayer 305, said P type Si _xGe _1-xLayer 305 adopts selective epitaxial growth.

Wherein, the SOI substrate is made up of end silicon layer 301, buried regions oxide layer 302 and top silicon layer 303, and silicon layer of the said end 301 is single crystal silicon material with top silicon layer 303.N type top silicon layer 303 and P type Si _xGe _1-xLayer 305 has constituted the SiGe/Si heterojunction diode.

The manufacture method of above-mentioned non-refrigerated infrared detector spare is following:

SOI is provided substrate, and said SOI substrate has N type top silicon layer;

On the silicon layer of said N type top, adopt thermal oxidation method or CVD method to form oxide layer;

Adopt photoetching, etching technics to remove the said oxide layer of part, thereby expose the monocrystalline silicon layer below it, be used to form P type Si _xGe _1-xLayer;

The top silicon surface epitaxial growth P type Si that is exposing _xGe _1-xLayer, the substrate surface that is coated with oxide layer can growing P-type Si _xGe _1-xLayer, P type dopant ion can be at deposit Si _xGe _1-xMix in the layer process;

At last, produce the hanging structure and the lead-in wire of detector, draw reading circuit to the voltage signal of diode to the periphery through the method for photoetching, etching.

As shown in Figure 5; SiGe/Si heterojunction in the present embodiment is compared with the band structure of traditional monocrystal silicon PN junction, and the P type semiconductor district has than the low energy gap width, has lower conduction band barrier height; The transition that helps electronics is conducted electricity with participating in, thereby improves the detectivity of Infrared Detectors.

The above only is preferred embodiment of the present invention, is not the present invention is done any pro forma restriction.

Though the present invention discloses as above with preferred embodiment, yet be not in order to limit the present invention.Any those of ordinary skill in the art; Do not breaking away under the technical scheme scope situation of the present invention; All the method for above-mentioned announcement capable of using and technology contents are made many possible changes and modification to technical scheme of the present invention, or are revised as the equivalent embodiment of equivalent variations.Therefore, every content that does not break away from technical scheme of the present invention, all still belongs in the scope of technical scheme protection of the present invention any simple modification, equivalent variations and modification that above embodiment did according to technical spirit of the present invention.

Claims (10)

1. a non-refrigerated infrared detector spare is characterized in that, comprising:

The substrate that includes insulating barrier;

Si on the said substrate _xGe _1-xLayer, said Si _xGe _1-xComprise adjacent p type island region and N type district in the layer.

2. non-refrigerated infrared detector spare according to claim 1 is characterized in that, said substrate is the SOI substrate.

3. non-refrigerated infrared detector spare according to claim 1 is characterized in that, said substrate comprises the buried regions oxide layer on monocrystalline silicon layer and the said monocrystalline silicon layer, and said insulating barrier is the buried regions oxide layer.

4. according to each described non-refrigerated infrared detector spare of claim 1-3, it is characterized in that said Si _xGe _1-xLayer according to the variation energy gap of Ge component in the scope of 0.66-1.12eV.

5. the manufacture method of a non-refrigerated infrared detector spare is characterized in that, comprising:

Substrate is provided;

On said substrate, form Si _xGe _1-xLayer;

At said Si _xGe _1-xForm adjacent p type island region and N type district in the layer.

6. according to the manufacture method of the said non-refrigerated infrared detector spare of claim 5, it is characterized in that, when said substrate is the SOI substrate, on said substrate, form Si _xGe _1-xLayer adopts epitaxial growth technology.

7. according to the manufacture method of the said non-refrigerated infrared detector spare of claim 5, it is characterized in that, when said substrate is monocrystalline substrate, on said substrate, form Si _xGe _1-xLayer adopts epitaxial growth technology, also comprises then: be infused in monocrystalline substrate and Si through ion _xGe _1-xThe buried regions of the formation at the interface oxide layer of layer.

8. according to the manufacture method of the said non-refrigerated infrared detector spare of claim 5, it is characterized in that, when said substrate is monocrystalline substrate, on said substrate, form Si _xGe _1-xLayer adopts Si _xGe _1-xBody material and monocrystalline substrate bonding are made.

9. a non-refrigerated infrared detector spare is characterized in that, comprising:

SOI substrate, said SOI substrate have N type top silicon layer;

P type Si on the silicon layer of said N type top _xGe _1-xLayer, said P type Si _xGe _1-xLayer adopts selective epitaxial growth.

10. the manufacture method of a non-refrigerated infrared detector spare is characterized in that, comprising:

SOI is provided substrate, and said SOI substrate has N type top silicon layer;

On the silicon layer of said N type top, form oxide layer;

Remove the said oxide layer of part and expose following monocrystalline silicon layer;

The top silicon surface epitaxial growth P type Si that is exposing _xGe _1-xLayer.

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