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非接触迁移率测试是一种测试载流子浓度以及迁移率的新型方法,与传统的范德堡霍尔测试相比,具有无损测量和分层测试等诸多优点。分别采用传统的范德堡霍尔测试法和新型的非接触迁移率测试法对不同帽层厚度、不同掺杂浓度的GaAs PHEMT样品进行测试分析。结果表明,在盖帽层很薄的情况下,两种测试方法所测得的电子浓度以及迁移率一致,而在盖帽层较厚的情况下,由于受盖帽层重掺杂电子的影响,范德堡霍尔测试无法测得沟道内二维电子气(2DEG)浓度和迁移率,而非接触式迁移率测试法可以将盖帽层和沟道层分开,准确地测得沟道内2DEG浓度和迁移率。
Non-contact mobility test is a new method to test the carrier concentration and mobility. Compared with the traditional Vanderbilt Hall test, non-contact mobility test has many advantages such as non-destructive measurement and delamination test. The GaAs PHEMT samples with different cap thickness and doping concentration were tested and analyzed by the traditional Vanderbilt Hall test method and the new non-contact mobility test method respectively. The results show that the electron concentration and mobility measured by the two methods are the same when the cap layer is very thin. However, in the case of thick cap layer, due to the influence of heavy doping electrons in the cap layer, The Hall-Hall test can not measure 2DEG concentrations and mobility in the channel, whereas the non-contact mobility test separates the cap layer from the channel layer and accurately determines 2DEG concentration and mobility in the channel .