Patent ID: 7094610

Claim:
A method for forming a magnetic sensor, comprising: forming a first ferromagnetic layer; forming a second ferromagnetic layer above the first ferromagnetic layer; forming a semiconductor layer between the first and second ferromagnetic layers, wherein the semiconductor layer permits application from outside the magnetic sensor, of a magnetic field being sensed; forming a first δ-doped layer between the first ferromagnetic layer and the semiconductor layer; and forming a second δ-doped layer between the second ferromagnetic layer and the semiconductor layer, wherein at least a selected one of the first and second δ-doped layers satisfies a condition N d > 2 ⁢ ɛ 0 ⁢ ɛ ⁡ ( Δ - Δ 0 ) q 2 ⁢ l 2 , wherein N d and l represent a donor concentration and a thickness of the selected δ-doped layer; q represents a positive elementary charge; ∈ represents a relative permittivity of the semiconductor layer, ∈ 0 represents a permittivity of vacuum; Δ represents a potential barrier height on interfaces between the selected δ-doped layer and an adjacent one of the first and second ferromagnetic layers; and Δ 0 represents a height of a potential barrier formed in the semiconductor layer.