Engineering Research Equipment Grant: Reactive Ion Etching System

砷化镓和其他化合物半导体的蚀刻是用湿化学技术进行的。湿法化学蚀刻存在一些局限性，因此P.I.我们希望获得一个反应离子蚀刻（RIE）系统。由于动力学辅助化学过程，RIE提供了高度各向异性的蚀刻。由于减少了掩蔽图案的切割，这种各向异性蚀刻将允许定义比目前湿化学蚀刻能力更小的几何形状。在适当的条件下，可以获得接近于零的横向蚀刻速率。这对于处理砷化镓特别重要，因为与硅不同，砷化镓没有液体蚀刻剂，这将导致很少或根本不会削弱掩蔽图案。RIE的另一个优点是能够选择性地蚀刻层。这是由于所使用的蚀刻剂具有高选择性。然而，即使这种蚀刻剂的选择性是不可能的，人们仍然可以选择性地去除层与RIE由于易于合并的终点检测。终点检测是通过光谱方法监测一种或多种反应物或流出物，以确定何时已去除一层。

Etching of GaAs and other compound semiconductors is performed with wet chemical techniques. Wet chemical etching present several limitations, and therefore the P.I.'s wish to acquire a reactive ion etching (RIE) system. RIE provides highly anisotropic etching due to kinetically assisted chemical processes. This anisotropic etching will allow definition of smaller geometries than are currently possible with wet chemical etching capabilities due to a reduction in undercutting of masking patterns. With proper conditions, lateral etch rates close to zero can be obtained with RIE. This is particularly important for processing GaAs because unlike silicon, GaAs has no liquid etchants which will result in little or no undercutting of the masking pattern. Another advantage of RIE is the ability to selectively etch layers. This is due to the high selectivity of the etchants used. Howevern even when this etchant selectivity is not possible, one can still selectively remove layers with RIE due to the easy incorporation of end point detection. End point detection is the monitoring by spectrometric methods of one or more of the reactants or effluent to determine when a layer has been removed.