AVS 50th International Symposium
    Electronic Materials and Devices Thursday Sessions
       Session EM-ThM

Invited Paper EM-ThM4
Development of Ohmic Contact Materials for Compound Semiconductors

Thursday, November 6, 2003, 9:20 am, Room 321/322

Session: Materials for Interconnects and Contacts to Semiconductors
Presenter: M. Murakami, Kyoto University, Japan
Authors: M. Murakami, Kyoto University, Japan
M. Moriyama, Kyoto University, Japan
S. Tsukimoto, Kyoto University, Japan
Correspondent: Click to Email
Compound semiconductors have been extensively used in a variety of devices which Si semiconductor cannot function. Although wide gap compound semiconductors are attractive for light emitting diodes, ultra-violet laser diodes, and high frequency and/or high power devices, lack of reliable, low resistance ohmic contact materials for these compound semiconductors hinders development of these devices. Our studies on ohmic contacts for GaAs, SiC, and diamond (although not compound semiconductor) indicated that formation of an intermediate semiconductor layer (ISL) which reduced the barrier height and/or the width of the depletion region (formed at an interface between the contact metal and the semiconductor) was essential to prepare low resistance ohmic contacts. Thus, once key materials for ISL formation was found, reduction of the contact resistance was obtained in these contacts by annealing at an optimum temperature. However, materials to form ISL could not be found for InP, ZnSe, GaN, and InGaN. For these semiconductors, not only search of materials to form ideal ISL's by reacting with these compound semiconductors should be continued, but also another contact formation mechanism should be explored. Our recent activities for ohmic contact formation mechanisms for various compound semiconductors will be reviewed.