InP-Based Unipolar Heterostructure Diode for Vertical Integration, Level Shifting, and Small Signal Rectification

抄録

A unipolar n-n heterostrucuture diode is developed in the InP material system. The electronic barrier is formed by a saw tooth type of conduction band bending which consists of a quaternary In_0.52(Al_yGa_1-y)_0.48As layer with 0 < y < y_max•. This barrier is lattice matched for all y to InP and is embedded between two n⁺-InGaAs layers. By varying the maximum Al-content from y_{max, 1} =0.7 to y_{max, 2} =1 a variable barrier height is formed which enables a diode-type I-V characteristic by epitaxial design with an adjustable current density within 3 orders of magnitude. The high current density of the diode with the lower barrier height (y_{max, 1} = 0.7) makes it suitable for high frequency applications at low signal levels. RF measurements reveal a speed index of 52ps/V at V_D = 0.15V. The device is investigated for RF-to-DC power conversion in UHF RFID transponders with low-amplitude RF signals.