Implanted Contacts for Diamond Semiconductor Devices

摘要

Key to future diamond semiconductor development are ohmic and Schottky contactsthat are stable at high temperature. Wide bandgap materials such as diamond (5.5 eV), pose special problems and demand ingenious solutions. Prior to our work, recent research into stable ohmic and Schottky contacts had been primarily limited to e-beam evaporation of carbide forming metals such as Ti, Ta, and Mo. These approaches have been relatively successful at decreasing the specific contact resistivity to as low as 10 to the-5 power ohm centimeter on natural semiconducting diamond with about 10 to the 16th power boron atoms per cubic centimeter. In our Phase I SBIR program we investigated metal systems coupled with a shallow Si implant that would form low resistivity, high temperature stable metal silicides. We showed in our Phase I results that the barrier height of metals such as Pt, Ti and Mo were reduced when deposited on shallow Si implants and given a heat treatment at 500C. The barrier height of Pt on diamond was reduced from 1.89 eV to 0.97 eV by annealing of a sputtered Pt contact on a Si implanted dose of 10 to the 15th power 1/centimeter squared A into the diamond surface. Using the same approach, the barrier height of Ti on diamond was reduced from 2.00 eV to 1.29 eV.