Thermally Stable Novel Metal Contacts on Bulk, Single-Crystal n-type ZnO

摘要

The contact characteristics on bulk single-crystal n-type ZnO of TiB2/Pt/Au, ZrB_2/Pt/Au and Ir/Au metallization schemes deposited by sputtering are reported as a function of annealing temperature in the range 200-1000℃ (N2 ambient). Boride contacts exhibited Ohmic behavior with minimum specific contact resistance between 10~(-3) and 10~(-5) Ωcm2 after a 700℃ or above anneal. The contacts transition to rectifying behavior after annealing above 900℃, coincident with a degraded surface morphology. Ir contacts exhibit higher thermal stability than both Boride contacts investigated, exhibiting a minimum specific contact resistance of 3.6 × 10~(-6) Ωcm2 after annealing at 1000℃. Ir contacts showed very little change in resistance after extended aging (30 days) at 350℃.