BACKGROUND:  Field effect transistors (FETs) provide a fundamental building block for electronic devices. Unlike conventional FETs, spin FETs are based on the manipulation of electronic spin states of electrical carriers. Spin FETs require an injector to introduce spin-polarized electrical carriers into the channel region. Diffusion-based current injection and tunnel injection have been used to inject charge carriers. However, diffusion-based current injection suffers from the electrical conductivity mismatch between ferromagnetic materials and semiconductors, prohibiting efficient spin injection. Tunnel injection suffers from high contact resistance which is detrimental to FET operations.

INNOVATION:  The fundamentally new approach for efficient spin injection can inject charge carriers such that near 100% of the charge carriers are spin polarized. The approach avoids the drawbacks and shortcomings associated with diffusion-based current injection and tunnel injection. The spin injector can enable viable spin FETs composed of ferromagnetic material sandwiched between two semiconductors, which may potentially provide an alternative to Si CMOS electronics.

POTENTIAL APPLICATIONS 

• Spintronics
• Spin FETs
• Alternatives to Si CMOS devices

ADVANTAGES

• Injects charge carriers efficiently with near 100% spin polarization
• Avoids high contact resistance

Reference: UCLA Case No. 2006-689