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GaAs集成电路要求FET有一致的夹断特性,而半绝缘GaAs衬底的质量对Si全离子注入的MESFET有着重大影响。这是由于高阻衬底中的Cr在离子注入和高温退火后的再分布,注入后载流子分布出现翘尾,使部分器件呈现出异常输出特性,表现为夹断电压偏高,小电流时跨导偏低,难以获得均匀的夹断电压。在N型有源层之下,用离子注入工艺形成一个隐埋的P型层,可以大大改善夹断电压的均匀性。已有报道,通过在沟道层和衬底之间引入一P型层,亚微米栅GaAs MSFET的短沟道效应有效地被抑制了,背栅效应对于GaAs集成电路无疑是有害的,模拟计算也表明,使用近补偿的衬底材料或缓冲层可使背栅沟道电容减至最小。
GaAs ICs require a consistent pinch-off of the FET, while the quality of the semi-insulating GaAs substrate has a significant impact on Si all-ion implanted MESFETs. This is due to the redistribution of Cr in the high-resistance substrate after ion implantation and high-temperature annealing. After the injection, the carrier distribution is crooked, causing some devices to exhibit abnormal output characteristics, showing high pinch-off voltage and small current When transconductance low, it is difficult to get a uniform pinch off voltage. Under the N-type active layer, the formation of a buried P-type layer by ion implantation can greatly improve the uniformity of the pinch-off voltage. It has been reported that the short-channel effect of a sub-micron gate GaAs MSFET is effectively suppressed by introducing a P-type layer between the channel layer and the substrate, which is undoubtedly detrimental to a GaAs integrated circuit. Simulations It also shows that back gate trench capacitance can be minimized using near-compensated substrate materials or buffer layers.