JPH0311897Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a Hall element using a compound semiconductor material, and particularly to a Hall element that prevents electrostatic damage.

(b) Conventional technology A Hall element is a magnetoelectric conversion element that converts magnetism into an electric signal, that is, a type of magnetic sensor.
It is used in a wide range of fields, such as controlling the rotation of brushless motors in VTRs, floppy disc devices, etc.

The conventional Hall element 21 is based on sensor technology (September 1985).
Monthly issue, Vo1.5.No.10), pages 68 to 71 (as detailed in Figure 2 A and Figure 2 B), semi-insulating
A GaAs substrate 22 , an N-type active region 23 formed by implanting silicon ions (Si ⁺ ) into the GaAs substrate 22 , and silicon ions (Si ⁺ ) implanted at the ends of the N-type active region 23 . An N ⁺ type contact region 24 formed by implantation, an insulating film 25 coated on the GaAs substrate 22, and an electrode 2 in ohmic contact with the N ⁺ type contact region 24.
6, and a thin metal wire 27 (indicated by a dotted line in the drawing) wire-bonded to electrically connect the electrode 26 and the lead.

On the other hand, the Hall element with the above-mentioned structure is
It is also described in detail in Publication No. 228783.

(c) Problems to be solved by the invention Although the Hall elements described above are becoming smaller, on the other hand, in order to wire-bond the thin metal wire 27 onto the electrode 26, the area of the electrode 26 is provided to be large. The need arose. Most of the area of this electrode 26 required for the wire bonding is in contact with the contact region 24 .

Therefore, as shown in FIG. 2B, there is a problem in that an electrostatic breakdown portion 28 is generated between the electrodes 26 at the interface between the electrically unstable GaAs substrate 22 and the insulating film 25.

(d) Means for solving the problems The present invention was made in view of the problems mentioned above, and in a Hall element using a compound semiconductor material, at least the substrate 2 made of the compound semiconductor material and the inside of the substrate 2 are provided. an active region 3 of one conductivity type formed in
a contact region 4 of one conductivity type with high impurity concentration formed at the end of the active region 3; a first insulating film 5 coated on the substrate 2; and the first insulating film 5.
a first electrode 7 that is in ohmic contact with the contact region 4 via a second insulating film 8 coated on the substrate 2; This problem is solved by making the first electrode 7 smaller than the second electrode 10.

(E) Function Active region 3 and contact region 4 are formed in the substrate 2.
After forming by ion implantation, the surface of this substrate 2 is coated with a silicon oxide film 5. Then, a hole is formed in the silicon oxide film 5 so as to make ohmic contact with the contact region 4, and a first electrode 7 is formed.

Here, if a second electrode 10 is further formed on the first electrode 7 to directly contact the thin metal wire 12 via the second insulating film 8, the dimensions of the first electrode 7 will be such that wire bonding is required. Moreover, since the contact resistance is low, it can be formed small.

Furthermore, after covering the second insulating film 8 with an insulating film 8 such as a silicon nitride film, a second electrode 10 is formed to have an area necessary for wire bonding.

Therefore, the first electrode 7 is made smaller than before and made of GaAs.
Since the distance between the first electrodes 7, 7 on the surface of the substrate 2 can be increased compared to the conventional one, the electrostatic breakdown resistance on the surface of the GaAs substrate 2 can be increased. Further, the interface of the second insulating film 8 made of silicon nitride film is the GaAs substrate 2.
Since the interface is extremely stable compared to the interface of

(F) Embodiment An embodiment of the Hall element 1 of the present invention will be described below with reference to FIG. 1A and FIG. 1B.

First, there is a semi-insulating GaAs substrate 2, an N-type active region 3 formed within the substrate 2, and an N ⁺ -type contact region 4 formed at the end of the active region 3.

Here, a non-doped silicon oxide film of about 5000 Å is coated on the substrate 2 by the CVD method, and the implantation energy is 150 KeV and the dose is 1×10 ¹³ cm ^-2 through an opening corresponding to the ion implantation region. Contact regions 4 are formed by implanting silicon ions. At this time, the silicon oxide film and the photoresist film used when forming the opening are used as a mask during ion implantation.

Similarly, the implantation energy for active region 3 is
Silicon ions are implanted at 360 KeV and at a dose of 4.2×10 ¹² cm ^-2 . Furthermore, for defect recovery and carrier recovery, a non-doped silicon oxide film of about 5000 Å is coated on both sides of the substrate 2, and then lamp annealed in an infrared heating furnace.

A contact hole 6 of the contact region 4 is formed by etching the silicon oxide film (first insulating film) 5 formed on the substrate 2, and a contact hole 6 is formed by vapor deposition through the contact hole 6. There is one electrode 7.

Here, the first electrode 7 is formed by depositing AuGe, Ni, Ti, and Au to thicknesses of about 1100 Å, 400 Å, 1000 Å, and 3000 Å, respectively. A lift-off method is adopted as a method for forming the first electrode 7, and in order to alloy the first electrode 7, alloying treatment is performed at about 400° C. for 1 minute in an infrared heating furnace. Further, the dimensions of the first electrode 7 are 120 μm×50 μm, and the dimensions of the contact hole are 110 μm×40 μm.

Next, a second insulating film 8 is formed on the surface of the substrate 2, a contact hole 9 is formed by etching the second insulating film 8, and the first electrode 7 is formed through the contact hole 9. There is a second electrode 10 in contact with.

Here, as the second insulating film 8, for example,
A silicon nitride film of about 1500 Å is formed on the surface of the substrate 2 using the CVD method. Further, a second electrode 10 is formed through a contact hole 9 formed by etching the silicon nitride film, and the second electrode 10 is in contact with the first electrode 7. , 3000Å by vapor deposition. Further, the dimensions of the second electrode 10 are 140 μm×70 μm, and the dimensions of the contact hole are 98 μm×28 μm.

Finally, ferrite 11, which is a ferromagnetic material, may be bonded to the lower surface of the substrate 2.

Further, explanations and drawings of structures such as wire bonding and resin molding, which will be subsequent steps, will be omitted here.

The feature of the present invention lies in the first electrode 7 and the second electrode 10.

Conventionally, in order to wire-bond a thin metal wire onto an electrode, it was necessary to provide a large electrode area. Therefore, as shown in FIG. 2B, an electrostatic breakdown portion 28 was generated between the electrodes at the interface of the GaAs substrate 22.

In order to solve this problem, the first electrode 7
is smaller than the second electrode 10, and a second insulating film 8 is formed on the first electrode 7 and the first insulating film 5.
was formed. Here, the first electrode 7 is 120 μm×
50μm, contact hole is 110μm x 40μm, second electrode 10 is 140μm x 70μm, contact hole is 98μm
The size was m×28 μm. Further, as the second insulating film 8, a silicon nitride film having a higher breakdown voltage than a silicon oxide film is used.

Therefore, in order to form the first electrode 7 smaller than the conventional one, the first electrodes 7, 7 on the surface of the GaAs substrate 2 are
Electrostatic damage between the two can be prevented. In addition, the second electrode 1
Since the second insulating film 8, which is much more stable than the GaAs interface, is present between the electrodes 10 and 10, electrostatic damage between the electrodes 10 and 10 can also be prevented.

Furthermore, the addition of the second electrode 10 and the second insulating film 8 can reduce the impact when wire-bonding the thin metal wire 12, thereby preventing property deterioration. Further, by employing the second insulating film 8, it is possible to prevent characteristic deterioration due to high temperatures and atmosphere.

(G) Effect of the invention As is clear from the above explanation, the first electrode 7 is made smaller than the second electrode 10, and a second electrode is further formed on the first electrode 7 and the first insulating film 5. By forming the insulating film 8, it is possible to prevent electrostatic discharge damage on the surface of the GaAs substrate 2 and deterioration of characteristics due to the atmosphere, and furthermore, it is possible to absorb shock during wire bonding.

Therefore, electrostatic damage to the Hall element can be prevented, and furthermore, characteristic deterioration during wire bonding can be prevented.

[Brief explanation of the drawing]

1A and 1B are a sectional view and a plan view of the Hall element of the present invention, and FIGS. 2A and 2B are a sectional view and a plan view of a conventional Hall element. 1 is a Hall element, 2 is a substrate, 3 is an N type active region, 4 is an N ⁺ type contact region, 5 is a first insulating film, 6 is a contact hole, 7 is a first electrode, 8 is a second , 9 is a contact hole, 10 is a second electrode, 11 is a ferrite, and 12 is a thin metal wire.

Claims (1)

[Scope of utility model registration request] a semi-insulating GaAs substrate, a cross-shaped active region formed on the surface of the substrate, and contact regions with high impurity concentration formed at four ends of the active region;
a first insulating film covering the surface of the substrate; a first electrode in ohmic contact with the surface of the contact region; and a second insulating film made of a silicon nitride film formed on the first insulating film. , the second
a contact hole opened in the insulating film; and a second electrode extending so as to be in contact with the electrode through the contact hole and overlying the second insulating film; A Hall element characterized in that the distance between the second electrodes on the surface of the second insulating film is closer than the distance between the first electrodes on the surface of the substrate.