Diamondlike carbon films on semiconductors for insulated‐gate technology

Carbon dielectric films with diamondlike properties were investigated as a new electronic material in a metal–insulator(carbon)–semiconductor (MIS) device configuration for solid state power devices for space applications. Films were directly deposited on the InP, GaAs, and Si substrates by ionizing a 25 vol % mixture of methane in argon using both single and dual ion beam systems. Electrical measurements at various frequencies of metal–carbon–InP devices showed a turn on voltage of −1.6 V with 0.2 V hysteresis, a fixed charge number density of 8×10¹⁰/cm², and an interface state density of 3.0×10¹² cm⁻² eV⁻¹. The capacitance–voltage (C–V) characteristics for carbon on GaAs were stretched out with 1.1 V hysteresis and indicated a fixed charge number density of 1×10¹²/cm² and an interface state density of 1×10¹³ cm⁻² eV⁻¹. The MIS device performance improved significantly due to in situ ion beam treatment of the semiconductor surfaces prior to the film deposition. This was determined to be related to oxygen at the film–semiconductor interface as determined by scanning Auger electron spectroscopy.