Hall effect sensor

• US 5,442,221 A
• Filed: 05/24/1993
• Issued: 08/15/1995
• Est. Priority Date: 05/27/1992
• Status: Expired due to Term

• Current Assignee: Itron, Inc.
• Original Assignee: Schlumberger Industries Incorporated (Schlumberger NV)
• Inventors: Mosser, Vincent, Robert, Jean-Louis
• Primary Examiner(s): Crane, Sara W.
• Assistant Examiner(s): GUAY, JOHN FRANCIS
• Application Number:
  US08/065,003
• Time in Patent Office: 813 Days
• Field of Search: 257/14, 257/15, 257/18, 257/22, 257/425, 257/190, 257/194, 257/422, 257/414, 257/421, 257/425, 257/426, 338/32 R, 338/32 H, 324/252, 324/260
• US Class Current: 257/425
• CPC Class Codes: H10N 52/101 Semiconductor Hall-effect devices

Abstract

A Hall effect sensor of two-dimensional electron gas type comprising, on an insulating substrate, a quantum well structure, a carrier injection layer adjacent to the quantum well structure, of thickness less than 250 Å and having an density per unit area of donors integrated over the whole thickness of the carrier injection layer less than 5×10¹² cm^-2, an insulating burial layer deposited on the carrier injection layer, having a conduction band with an energy level greater than the Fermi energy of the sensor and a thickness greater than 200 Å. Applicable to the field of electricity meters and current sensors.

Claims

1. A Hall effect sensor comprising:

a) a quantum well structure having

i) a first layer of a III-V semiconductor material,

ii) a second layer of a III-V semiconductor material, and

iii) a third layer of III-V semiconductor material deposited on a semiconductor substrate, the III-V material of the second layer having a forbidden band gap narrower than that of the III-V materials of the first and third layers;

b) a fourth layer superimposed on the third layer and doped with donor type impurities, said fourth layer having a thickness less than 250 Å

, and a carrier density per unit area integrated over the whole fourth layer less than 5×

10¹² cm^-2 ; and

c) a fifth layer of III-V semiconductor material superimposed on said fourth layer, said fifth layer having a thickness greater than 200 Å

, which is not doped or is doped with acceptor type impurities, wherein the conduction band of said fifth layer has a higher energy than the energy of the conduction band of the second layer, and said second layer of III-V semiconductor material has a forbidden band gap of smaller width than the forbidden band gap of said first layer, and said third layer of III-V semiconductor material has a forbidden band gap of greater width than the forbidden band gap of the first layer.

2. A sensor according to claim 1, wherein the first layer of III-V semiconductor material functions as a buffer between the substrate and the quantum well.

3. A sensor according to claim 1, wherein the fourth layer has a thickness which is nominally zero, the dopant being deposited in the thickness of an atomic plane of a layer adjacent to the fourth layer.

4. A sensor according to claim 1, wherein the substrate is Si or GaAs.

5. A sensor according to claim 4, wherein the second layer is In_x Ga_1-x As with a value of x in a range from 0 to 0.4 and a thickness in the range from 10 Å

to 500 Å

.

6. A sensor according to claim 4, wherein the third layer is Al_y Ga_1-y As with a value of y in a range from 0 to 0.4 and a thickness less than 200 Å

.

7. A sensor according to claim 4, wherein the third layer is formed by a AlAs/GaAs superlattice with a short period forming a pseudo-alloy.

8. A sensor according to claim 4, wherein the fourth layer is Al_u Ga_1-u As with a value of u in a range from 0 to 0.4, the fourth layer being doped with an n-type dopant pertaining to a group of the periodic table selected from groups IV and VI.

9. A sensor according to claim 4, wherein the fourth layer is formed by an AlAs/GaAs superlattice with a short period forming a pseudo-alloy, the fourth layer being doped with an n-type dopant of the periodic table selected from groups IV and VI.

10. A sensor according to claim 4, wherein the fifth layer is Al_u Ga_1-u As with a value of u in a range from 0 to 0.4.

11. A sensor according to claim 4, wherein the fifth layer is formed by an AlAs/GaAs superlattice with a short period forming a pseudo-alloy.

12. A sensor according to claim 4, wherein the fifth layer comprises a first sublayer of an alloy or pseudo-alloy of Al_p Ga_1-p As with a value of p in a range from 0 to 0.4 and a second sublayer of Al_w Ga_1-w As having a composition gradient, w going from p to zero.

13. A sensor according to claim 1, wherein the substrate is InP.

14. A sensor according to claim 13, wherein the second layer is In_x Ga_1-x As with a value of x from 0.5 to 0.56 and a thickness in a range from 10 Å

to 500 Å

.

15. A sensor according to claim 14, wherein the third layer is In_y Ga_1-y As with a value of y from 0.5 to 0.56 and a thickness less than 200 Å

.

16. A sensor according to claim 13, wherein the fourth layer is formed of In_v Al_1-v As with the value of v in a range from 0.5 to 0.56, said fourth layer being doped with an n-type dopant selected from groups IV and VI of the periodic table.

17. A sensor according to claim 14, wherein the fifth layer is In_z Al_1-z As with the value of z from 0.5 to 0.56.

18. A sensor according to claim 1, further comprising, symmetrical with said fourth layer, a sixth layer adjacent to the quantum well structure.