交/直流薄膜方块电阻测试系统设计与分析

Design and Analysis of Test System for Thin Film Sheet Resistance by AC/DC Methods

四探针法测量薄膜方块电阻具有测量精度高、稳定性好等优点,被广泛应用于薄膜器件制备、半导体微区掺杂等领域。为了提高薄膜方块电阻的测试速度及精度,以改进的范德堡法原理为基础,采用压控电流源方式输出稳定的电流,利用LabVIEW软件搭建了一套能使用交/直流测量薄膜方块电阻的测试系统。为了验证该测试系统的合理性及测试速度,选取Pt金属薄膜作为被测样品进行方块电阻的测量。测试结果表明,直流法和交流法都能精确测量薄膜方块电阻,直流法和交流法的单次测试时间分别为0378 s和0317 s,系统的测试速度优于商用280SI半导体设备。交流法测试Pt金属薄膜方块电阻的抗干扰能力比直流法强。该系统为被测样品选取合适的测试电流和测试方法提供了参考,对薄膜样品进行变温电阻率连续测量具有重要意义。

The four-probe method for measuring the sheet resistance of thin film is widely used in the fields of thin film device fabrication and semiconductor microdoping due to its advantages of high measurement accuracy and good stability.To improve the test speed and accuracy of the sheet resistance of thin film,based on the principle of van der Pauw method,a voltage controlled current source was used to output stable current.A sheet resistance test system was designed by using LabVIEW software that can measure the sheet resistance of thin film under alternating-current(AC)and direct-current(DC)modes.In order to verify the rationality and test speed of the test system,a Pt metal thin film was selected as the tested sample to measure the sheet resistance.The test results show that both DC and AC methods can accurately measure the sheet resistance of the thin film.The individual test time of DC and AC methods are 0378 s and 0317 s,respectively.The test speed of the system is better than that of commercial 280SI semiconductor decive.The anti-interference ability of the AC method for testing the sheet resistance of Pt metal thin film is better than that of the DC method.This system provides a reference for selecting appropriate test currents and methods for the tested samples,and has great significance for the continuous measurement of the variable temperature resistivity of thin film samples.