High Quality MPCVD Epitaxial Diamond Film for Power Device Application
- PDF / 398,078 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 38 Downloads / 247 Views
B7.2.1
High Quality MPCVD Epitaxial Diamond Film for Power Device Application Jie Yang1,2, Weixiao Huang3, T.P. Chow3, and James E. Butler1 1, Gas/Surface Dynamics Section, Naval Research Laboratory, Washington DC 20375, U.S.A. 2, NOVA Research Inc., Alexandria, VA 22308, U.S.A. 3, Rensselaer Polytechnic Institute, Troy, NY 12180, U.S.A. ABSTRACT As a wide bandgap (5.47 eV) semiconductor material, single crystal diamond has high electron mobility (reportedly between 2000 and 4400 cm2V-1s-1), high electron saturation velocity (2x107 cms-1), high breakdown voltage (>107 Vcm-1), and high thermal conductivity (>21 Wcm-1K-1). Diamond-based semiconductor devices offer the potential of operation at high voltages, power levels, temperatures and under extreme radiation conditions. In this work, we present our effort to grow high quality homo-epitaxial diamond films on (100)-single crystal diamond substrates by microwave plasma chemical vapor deposition (MPCVD). The growth rate can vary from 0.01 to 100 micrometers per hour, depending on growth conditions, doping, and quality; and using a “lift-off” process, free-standing homo-epi films with remarkably low p-type doping (1x1014 –1x1017 cm-3) and exceptionally low compensation ~ 1x1013 cm-3 have been made. Vertical and lateral structure high voltage diamond Schottky rectifiers have been built for frequency dependent capacitance-voltage (C-V), and current-voltage (I-V) measurements. A breakdown voltage of 8 kV at 100 µm distance and 12.4 kV at 300 µm distance is recorded for lateral structure devices without Ohmic contact (back to back Schottky contacts), while an un-optimized vertical device with an back-side Ohmic contact has demonstrated a forward voltage drop of 7 V at 18 A/cm2 in a device that can only block 600 V. New test results show 3.7 kV blocking voltage vertical devices on 20 µm freestanding MPCVD diamond film. This data shows that the quality of diamond film extremely affect the electrical properties of the built devices. INTRODUCTION Diamond is famous for its mechanical properties, well known as the hardest of all materials. Diamond is also especially attractive as a semiconductor because of its unique combination of good electrical, optical, thermal and chemical properties. Diamond has a larger bandgap (5.5 eV) than SiC (3.4 eV), GaN (3.2 eV) and Si (1.1 eV) [1] which should enable the fabrication of diodes with larger breakdown voltages than exhibited by diodes formed in the other semiconductors. However, diamond diodes and transistors have rarely exhibited breakdown voltages in excess of 500 V [2,3], while diodes formed in the other semiconductors exhibit significantly higher breakdown [4]. Important to electronic application of diamond is the control of the diamond crystal growth to obtain semiconductor quality. By control the doping level during the chemical vapor deposition (CVD) of homo-epitaxial diamond films, some recent work shows exciting results. In reference [5], high-voltage blocking properties (>6 kV) have been shown for lateral devices using high-
Data Loading...
