金刚石肖特基二极管的研究进展

Diamond has excellent material properties such as wide band gap (5. 47 eV), high carrier mobility (3 800 cm² / (V·s) for holes and 4 500 cm² / (V·s) for electrons), high thermal conductivity (22 W·cm ^{- 1} ·K ^{- 1} ), high critical breakdown field strength (> 10 MV / cm), and optimal Baliga’ s figure of merit, which make diamond semiconductor devices ideal choices for the applications in extreme conditions such as high temperature, high frequency, high power, and strong irradiation. With the breakthroughs in diamond crystal growth by CVD techniques and p-type doping of diamond crystal, research on Schottky barrier diode (SBD) based on boron-doped diamond has been widely carried out. In this review, the working principles of the diamond SBD are introduced in detail. The growth processes of highly doped p-type thick films, p-type films of low doping drift region are investigated, and the conditions for the formation of ohmic contact and Schottky contact between different metals and diamond crystals are studied. Then the preparation processes of transverse, vertical and pseudovertical device structures and their effect on forward, reverse and breakdown characteristics of the SBDs are analyzed. The modulation of the internal electric field of SBDs by device structures like field plate, passivation layer and edge terminal, which strengthens the reverse breakdown voltage of the device, is illustrated. Finally, the application prospects and challenges of diamond SBDs are summarized.