金刚石硼掺杂准垂直肖特基二极管特性研究

Study on the Characteristics of Boron-doped Pseudo Vertical Diamond Schottky Barrier Diodes

金刚石是超宽禁带半导体材料的典型代表,因其优异的材料特性,在高温、高频、大功率微波和电力电子器件应用中有着显著的优势。金刚石体掺杂p型二极管由于工艺简单、并且有望发挥出金刚石击穿场强高的特性。采用微波等离子体化学气相沉积设备实现了单晶金刚石外延过程中硼掺杂浓度的调控,在金刚石本征衬底上制备出p^(-)/p^(+)结构的金刚石外延层,掺杂浓度分别为1018 cm^(-3)和1020 cm^(-3)。进而采用该结构制备了金刚石准垂直结构的肖特基二极管器件。测试结果表明,器件正向导通电阻为90 mΩ·cm^(2),开启电压约为-1.68 V,反向击穿场强为2.4 MV/cm,归一化后的电流密度为53.05 A/cm^(2)。计算得该器件中漂移层的载流子浓度为1.16×10^(18)cm^(-3)。

Diamond is a typical representative of ultra-wide bandgap semiconductor materials.It has significant advantages in high-temperature,high-frequency,high-power microwave,and power electronic device applications due to its excellent material properties.P-type doped diamond diode have attracted widespread attention due to its simple process and potential to exhibit high diamond breakdown field strength.In this study,microwave plasma chemical vapor deposition equipment is used to control the boron-doped concentration during the epitaxy process of single-crystal diamond,and diamond epitaxial layers with p^(-)/p^(+)structure are prepared on diamond intrinsic substrates,with doping concentrations of 1018 cm^(-3)and 1020 cm^(-3),respectively.Subsequently,a diamond Schottky diode device with a pseudo vertical structure is fabricated using the structure.The test results show that the forward on-resistance of the device is 90 mΩ·cm^(2),the turn-on voltage is about-1.68 V,the reverse breakdown field strength is 2.4 MV/cm,and the normalized current density is 53.05 A/cm^(2).The carrier concentration of the drift layer in the device is calculated to be 1.16×10^(18)cm^(-3).The on-resistance and breakdown field strength of the device reaches international advanced level.In subsequent studies,it is expected that the breakdown performance of the device can be improved by further increasing the thickness of the light doped layer.