阅读说明：本技术 半导体装置 (Semiconductor device ) 是由 飞冈孝明 于 2019-05-15 设计创作，主要内容包括：本发明涉及半导体装置。霍尔元件具备：磁感受部(20),由在第一导电型的半导体基板(10)设置的第二导电型的杂质扩散层构成,在俯视下具有四个端部；以及四个电极(31)~(34),在磁感受部的表面由在四个端部的各个设置的比磁感受部高浓度的第二导电型的杂质扩散层构成,作为磁感受部的杂质扩散层离半导体基板的表面具有第一深度(D1),具有第二导电型的杂质浓度从半导体基板的表面起到比第一深度浅的第二深度(D2)为止朝向深度方向变高的第一浓度梯度(S1),具有第二导电型的杂质浓度从第二深度起到第一深度为止朝向深度方向变低的第二杂质梯度(S2),第二深度为第一深度的一半以下,第一浓度梯度比第二浓度梯度陡峭。(The present invention relates to semiconductor devices.Hall element has: magnetic strength is made of, there are four ends for tool under vertical view by portion (20) the impurity diffusion layer of the second conductive type of semiconductor substrate (10) setting in the first conductive type；And four electrode (31) ~ (34), it is made of the ratio magnetic strength of each setting four ends by the impurity diffusion layer of the second conductive type of portion's high concentration in magnetic strength by the surface in portion, there is the first depth (D1) by the surface of the impurity diffusion leafing semiconductor substrate in portion as magnetic strength, impurity concentration with the second conductive type plays the first concentration gradient (S1) got higher until the second depth (D2) than the first depth as shallow towards depth direction from the surface of semiconductor substrate, the second impurity gradient (S2) that impurity concentration with the second conductive type is lower until playing the first depth from the second depth towards depth direction, second depth is less than half of the first depth, first concentration gradient is more precipitous than the second concentration gradient.)

1. a kind of semiconductor device, comprising:

The semiconductor substrate of the first conductive type；And

Hall element is arranged at the semiconductor substrate,

The semiconductor device is characterized in that,

The Hall element has:

Magnetic strength is made of the impurity diffusion layer for the second conductive type being arranged in the semiconductor substrate, is had under vertical view by portion Four ends；And

Four electrodes are high by portion by surface magnetic strength as described in the ratio of each setting in four ends in portion in the magnetic strength The impurity diffusion layer of the second conductive type of concentration is constituted,

Surface as semiconductor substrate described in impurity diffusion leafing of the magnetic strength by portion has the first depth, has second to lead Direction is deep until the impurity concentration of electric type plays the second depth than first depth as shallow from the surface of the semiconductor substrate The first concentration gradient that degree direction is got higher, the impurity concentration with the second conductive type play described first deeply from second depth The second impurity gradient being lower until degree towards depth direction, second depth are less than half of first depth, institute It is more precipitous than second concentration gradient to state the first concentration gradient.

2. semiconductor device according to claim 1, which is characterized in that the magnetic strength is miscellaneous by the second conductive type in portion Depth of the matter concentration on the surface from the semiconductor substrate is 400nm to having peak value between 800nm, and the concentration of the peak value is 1×10¹⁶atoms/cm³To 1 × 10¹⁷atoms/cm³Between, the magnetic strength is 2 ~ 5 μm by the depth in portion.

3. semiconductor device according to claim 1, which is characterized in that the magnetic strength is had square by portion under vertical view Shape or cross.

4. semiconductor device according to claim 2, which is characterized in that the magnetic strength is had square by portion under vertical view Shape or cross.

5. described in any item semiconductor devices according to claims 1 to 4, which is characterized in that be also equipped with and surround the magnetic strength By be set to around portion and in the way of being separated with the magnetic strength by portion the semiconductor substrate, than the semiconductor substrate The element of the first conductive type of high concentration separates diffusion layer.

6. described in any item semiconductor devices according to claims 1 to 4, which is characterized in that the semiconductor substrate and institute Magnetic strength is stated to be covered other than being provided with the region of the electrode by insulating film by the surface in portion.

Technical field

The present invention relates to semiconductor devices, more particularly to the semiconductor device with Hall element.

Background technique

Hall element due to can be used as Magnetic Sensor carry out it is non-contact under position sensing or angle sensing, so by with In various uses.

For actual Hall element, even if also generating output voltage when being not applied to magnetic field.It will be at the magnetic field 0 The voltage of output is known as offset voltage.Offset voltage Producing reason is considered as due to the machinery by applying externally to element Stress or alignment (alignment) deviation in the fabrication process etc. caused by Potential distribution inside element it is unbalanced. In the case where Hall element is used as Magnetic Sensor, need to remove such offset voltage.

In order to remove (elimination) offset voltage, usually using rotatory current method.

Hall element can equivalent circuit as shown in Figure 3 indicate.That is, Hall element be represented as by 4 resistance R1, R2, R3, R4 4 terminals T1, T2, T3, T4 are connected after bridge circuit.

In such a circuit, in order to carry out rotatory current method, firstly, supplying electricity for terminal T1, T2 as driving current Pole applies voltage Vin using terminal T3, T4 as Hall voltage output electrode between Xiang Duanzi T1-T2.As a result, in terminal T3-T4 Between generate output voltage Vh+Vos.Then, electrode is supplied using terminal T3, T4 as driving current, using terminal T1, T2 as Hall Voltage output electrode applies voltage Vin between Xiang Duanzi T3-T4.Output voltage-Vh+Vos is generated between terminal T1-T2 as a result,. Here, Vh shows the Hall voltage of the Hall element proportional to magnetic field, Vos shows offset voltage.

Output voltage when by flowing from electric current to the two above directions subtracts each other, to eliminate offset voltage Vos, energy Access the output voltage 2Vh proportional to magnetic field.

The resistance value of resistance R1, R2, R3, R4 are unbalanced and uneven due to the Potential distribution inside element, it generates Offset voltage Vos, still, offset voltage Vos can be eliminated by carrying out rotatory current method as described above.

But in the case where the resistance value of resistance R1, R2, R3, R4 change according to the application direction of voltage, no Offset voltage can be completely removed.

In common Hall element, the periphery of Hall element surrounded magnetic strength is become by the extrinsic region of the N-type in portion Portion be p-type extrinsic region so as to other region disconnectings (referring to patent document 1).When in order to magnetic strength by portion supply electric current And when applying voltage to driving current supply electrode, depletion layer expands to side of the magnetic strength by portion and its peripheral portion of Hall element Boundary.Since electric current does not flow in depletion layer, so, inhibit electric current in the region that magnetic strength is extended by depletion layer in portion, the portion The resistance value divided increases.In addition, depletion width depends on the application direction of voltage and changes, it is therefore, shown in Fig. 3 etc. The resistance value for imitating resistance R1, R2, R3, R4 of circuit changes according to the application direction of voltage.Therefore, even if executing rotation Current method also eliminates endless offset voltage.

For such problems, in patent document 2, propose by configuring depletion layer in component periphery and member upper Coordination electrode is adjusted to the voltage that each electrode applies and the method that inhibits depletion layer to extend into Hall element.As a result, can It enough carries out eliminating using the offset of rotatory current method.

Summary of the invention

Therefore, the purpose of the present invention is to provide have can without using complicated control circuit high-precision Ground removes the semiconductor device of the Hall element of offset voltage.

Solution for solving the problem

Semiconductor device of the invention is a kind of semiconductor device, comprising: the semiconductor substrate of the first conductive type；And Hall Element is arranged at the semiconductor substrate, and the semiconductor device is characterized in that the Hall element has: magnetic strength by Portion is made of the impurity diffusion layer for the second conductive type being arranged in the semiconductor substrate, and there are four ends for tool under vertical view；With And four electrodes, it is highly concentrated by portion by surface magnetic strength as described in the ratio of each setting in four ends in portion in the magnetic strength The impurity diffusion layer of the second conductive type of degree is constituted, as semiconductor substrate described in impurity diffusion leafing of the magnetic strength by portion Surface has the first depth, and the impurity concentration with the second conductive type is played from the surface of the semiconductor substrate than described first The first concentration gradient got higher until second depth of depth as shallow towards depth direction, with the second conductive type impurity concentration from The second impurity gradient that second depth is lower until playing first depth towards depth direction, second depth are Less than half of first depth, first concentration gradient are more precipitous than second concentration gradient.

Invention effect

According to the present invention, the magnetic strength with the first depth is had by portion and has the impurities concentration distribution of peak value in the second depth.Cause This, is when application voltage is supplied electric current by portion to magnetic strength between two opposite electrodes among four electrodes, the electric current collection In flowed in magnetic strength by highest second depth part of impurity concentration in portion.Second depth is less than half of the first depth Depth, that is, magnetic strength by portion shallower part, also, the second concentration gradient S2 mitigate, therefore, can prevent from magnetic strength by portion Bottom and semiconductor substrate knot generate depletion layer among reached second by the depletion layer that portion side extends in magnetic strength Depth.Therefore, electric current can be prevented due to depletion layer and be suppressed and resistance value increase.That is, can prevent to four electrodes Among two opposite electrodes between when applying voltage and to electricity each when applying voltage between another two opposite electrode The resistance value of interpolar changes.Therefore, offset voltage can accurately be removed using rotatory current method.Furthermore, it is not necessary that Inhibit electrode or the circuit of complexity therefore chip size can be made to become smaller, also be able to suppress cost using depletion layer.

Detailed description of the invention

Fig. 1 (a) is the plan view of the semiconductor device with Hall element of embodiments of the present invention, and Fig. 1 (b) is edge The sectional view of the L-L line of Fig. 1 (a).

Fig. 2 is another plan view for showing Hall element shown in FIG. 1.

Fig. 3 is the equivalent circuit diagram of Hall element.

Specific embodiment

It is described in detail hereinafter, Duiing mode for carrying out the present invention while referring to attached drawing.

Fig. 1 is the figure for illustrating the semiconductor device with Hall element 100 of an embodiment of the invention, figure It 1(a) is plan view, Fig. 1 (b) is the sectional view along the L-L line of Fig. 1 (a).As shown in Figure 1, present embodiment is partly led Body device has: the semiconductor substrate 10 of p-type (the first conductive type), semiconductor substrate 10 be arranged Hall element 100 and The element for the p-type being arranged in the mode surrounded around Hall element 100 separates diffusion layer 50.

Hall element 100 has: being made of the impurity diffusion layer for the N-type (the second conductive type) being arranged in semiconductor substrate 10 And the magnetic strength under vertical view with square shape by portion 20 and magnetic strength by portion 20 surface by the ratio magnetic that is arranged in each end Electrode 31 ~ 34 that the extrinsic region of the N-type of 20 high concentration of impression portion is constituted is constituted.

In addition, in Hall element 100, in magnetic strength by surface setting insulating film (such as the SiO in portion 20₂Film) 40, so that Cover the region other than being provided with the region of electrode 31 ~ 34.

The impurity that the magnetic strength of semiconductor substrate 10 and N-type that p-type is shown on the right side of Fig. 1 (b) is included by portion 20 Concentration profile (profile).

From the concentration profile it is found that surface of the magnetic strength by portion 20 from semiconductor substrate 10 has the first depth D1, there is N The impurity concentration of type is played until the second depth D2 more shallow than the first depth D1 from the surface of semiconductor substrate 10 towards depth side To the first concentration gradient (concentration gradient) S1 got higher, have the impurity concentration of N-type from the second depth D2 The second concentration gradient S2 being lower until playing the first depth D1 towards depth direction.

In addition, the second depth D2 is less than half of the first depth D1, the first concentration gradient S1 is than the second concentration gradient S2 It is precipitous.

There is the depth that N-type impurity is injected in region of the magnetic strength by portion 20 to D2 by the formation in such as semiconductor substrate 10 And the N-type impurity is set to be diffused into the depth of D1, to obtain having the magnetic strength of such concentration distribution by portion 20.

Preferably, it is 400 ~ 800nm that the impurity concentration of N-type, which is the depth D2 of peak value, which is 1 × 10¹⁶atoms/ cm³To 1 × 10¹⁷atoms/cm³Between.Moreover it is preferred that magnetic strength is 2 ~ 5 μm or so by the depth D1 in portion 20.

Element separation diffusion layer 50 is formed to be separated with magnetic strength by portion 20, by Hall element 100 and semiconductor substrate 10 Other regions (not shown) it is electrically separated.

In other of the semiconductor substrate 10 by the element of p-type separation diffusion layer 50 and Hall element 100 after electrically separated Region (not shown) in, be provided with the elements such as transistor for constituting circuit, the circuit is for handling from Hall element 100 output signal or the circuit that signal is supplied to Hall element 100.In order to form such element, the region extremely Few a part forms N trap (well).Can be formed in common process the N trap and as N-type impurity diffusion layer magnetic strength by Portion 20.Therefore, N trap has with magnetic strength by the identical depth in portion 20 and identical concentration distribution.Like this, according to this embodiment party Formula can form magnetic strength by portion 20 in the case where not increasing manufacturing process.

According to the semiconductor device of the present embodiment constituted as described above, when to opposite among electrode 31 ~ 34 When application voltage is supplied electric current by portion 20 to magnetic strength between electrode 32-33, the current convergence is in dense by impurity in portion 20 in magnetic strength It spends the part of highest second depth D2 and flows.Second depth D2 be the first depth D1 the depth, that is, magnetic strength of less than half by Shallower part in portion 20, also, the second above-mentioned concentration gradient S2 mitigates, and therefore, the magnetic strength from N-type can be prevented by portion Among the depletion layer (depletion layer) that the knot of the semiconductor substrate 10 of 20 bottom and p-type generates magnetic strength by The depletion layer of 20 side of portion extension reaches the second depth D2.Thereby, it is possible to prevent electric current to be suppressed due to the presence of depletion layer And the resistance value in the path of electric current flowing increases.That is, can prevent to the opposite electrode 32- among four electrodes 31 ~ 34 It changes when applying voltage between 33 and to resistance value when applying voltage between opposite electrode 31-34.Therefore, rotation can be utilized Current method accurately removes offset voltage.

In turn, according to the present embodiment, the element separation diffusion layer 50 and the magnetic strength of N-type for making p-type are separated by portion 20, make to compare Element separate the semiconductor substrate 10 of the p-type of 50 low concentration of diffusion layer between element separate diffusion layer 50 and magnetic strength by portion 20 it Between, it is also able to suppress as a result, from the lateral extension to magnetic strength by the depletion layer in portion 20, the depletion layer can be prevented in magnetic The electric current flowed in impression portion 20 affects.

Furthermore, it is not necessary that inhibiting the circuit of electrode or complexity using depletion layer, thus, it is also possible to which chip size is made to become smaller simultaneously And inhibit cost.

In turn, according to the present embodiment, it other than above-mentioned effect, also obtains that Hall element 100 can be made highly sensitive Effect as degree and low noise.Hereinafter, being illustrated to its reason.

It is known: in Hall element, by making magnetic strength be become larger by the electron mobility in portion, so as to improve sensitivity. That is, needing to make the magnetic strength of Hall element to be become smaller by the impurity concentration in portion to make Hall element high-sensitivity.

On the other hand, in Hall element, sheet resistance is lower, then gets over relative to the noise ratio of the output of Hall element It is small.

Since by portion 20, the impurity concentration with N-type plays second from the surface of semiconductor substrate 10 to magnetic strength as described above The the first concentration gradient S1 got higher until depth D2 towards depth direction, so, magnetic strength is by the N-type impurity near the surface in portion 20 Concentration is very small, and therefore, electric current hardly flows there.Due in semiconductor substrate 10(magnetic strength by portion 20) surface near There are interfacial state (interface state) or lattice defects (lattice defect), so, electron mobility reduces, but It is according to the present embodiment, hardly to be flowed in magnetic strength by electric current near 20 surface of portion, therefore, the drop of sensitivity can be prevented It is low.

In turn, in Hall element 100, as described above, insulating film 40 is set, so that surface of the covering magnetic strength by portion 20 The region in addition to being provided with electrode 31 ~ 34 other than region.Electric current can be further reliably not in magnetic strength by portion 20 as a result, The electron mobility on surface flows in lesser region.Thereby, it is possible to inhibit the reduction of sensitivity.

In addition, by making peak-peak concentration 1 × 10 of the magnetic strength by portion 20¹⁶atoms/cm³To 1 × 10¹⁷atoms/cm³ Left and right is less high, so that electron mobility be made to become larger, can be improved sensitivity.

In addition, as described above, magnetic strength is lower set by the concentration in portion 20 in order to make electron mobility become larger, but It is, correspondingly, by keeping magnetic strength deep by 2 ~ 5 μm of depth or so of portion 20, so as to reduce the thin of Hall element 100 Layer resistance, noise and the ratio of the output signal of Hall element 100 become smaller, and obtain stable output.

More than, embodiments of the present invention are illustrated, still, the present invention is not limited to above embodiment, Certainly it can be made various changes in the range of without departing from purport of the invention.

For example, in the above-described embodiment, making the first conductive type p-type and making the second conductive type N-type to be said It is bright, still, exchanges conductivity type and make the first conductive type N-type and make the second conductive type p-type can also.

In addition, in the above-described embodiment, the example that magnetic strength is had square shape by portion 20 under vertical view is shown, but It is that magnetic strength is not limited to this by the shape in portion 20, for example, as shown in Figure 2, or cross.

The explanation of appended drawing reference

100 Hall elements

10 semiconductor substrates

20 magnetic strengths are by portion

31,32,33,34 electrode

40 insulating films

50 elements separate diffusion layer

T1, T2, T3, T4 terminal

R1, R2, R3, R4 resistance.