Field effect transistor with an InSb quantum well and minority carrier extraction

摘要

A field effect transistor 10 and a method of forming said transistor comprises a quantum well 22 which is at least partially in an intrinsic conduction state when the transistor 10 is unbiased and is at a normal operating temperature. The transistor 10 includes means to bias the transistor such that charge carriers in the quantum well 22 are predominately those relating to a saturated extrinsic conduction state. The quantum well 22 may be a p-type InSb layer located between InAlSb layers 20, 24. Layer 24 may include an ultra-thin delta-doped Si layer 28 which provides a dominant source of charge carriers for the quantum well 22. Layer 20 may be formed on a barrier layer 19, a substrate layer 14 and a substrate 16. The transistor 10 may have an insulated gate electrode 34c and n+ source and drain layers 30a, 30b and electrodes 34a, 34b which may have a positive bias relative to a substrate electrode 18 such that they can provide minority carrier extraction in the quantum well 22, reducing the intrinsic contribution to conductivity. The transistor 10 may provide a predominately saturated extrinsic conduction state with low leakage current.