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原位测试了氢终结金刚石膜在氮气保护和大气气氛中加热时的表面导电特征,分析并讨论了该导电沟道的高温稳定性。结果表明,室温下氢终结金刚石表面电导率均在10~(-5)S量级。随着温度的升高,N_2气氛下的金刚石膜表面电导率呈现逐渐下降的趋势,而大气中加热的金刚石膜表面电导率则出现了明显的台阶式降低。对于后者而言,金刚石表面在120℃发生的第二层水分子脱附和230℃下CH基团的分解,是其电导率发生阶梯式下降的主要原因。而在氮气(N_2)气氛下氢终结金刚石膜表面导电沟道表现出更高的分子水脱附温度(300℃)和氢分解温度(400℃),表明气氛保护可有效提高氢终结金刚石表面导电沟道的稳定性。
The surface conductivity of hydrogen-terminated diamond films was tested in-situ when heated in nitrogen atmosphere and in the atmosphere. The high-temperature stability of the conductive channels was analyzed and discussed. The results show that the surface conductivity of hydrogen terminated diamond at room temperature is in the order of 10 ~ (-5) S. With the increase of temperature, the surface conductivity of diamond film in N 2 atmosphere shows a gradually decreasing trend, while the surface conductivity of diamond film heated in air has a significant step-down. For the latter, the desorption of the second layer of water molecules at 120 ° C on the diamond surface and the decomposition of CH groups at 230 ° C are the main reasons for the graded decline in conductivity. The conduction channel of hydrogen-terminated diamond films showed higher molecular water desorption temperature (300 ℃) and hydrogen decomposition temperature (400 ℃) under N2 atmosphere, indicating that atmosphere protection can effectively improve the surface conduction of hydrogen terminated diamond Channel stability.