Planarization of GaN by photoresist technique using an inductively coupled plasma

摘要

Films of III-nitride for semiconductor device growth are planarized using an etch-back method. The method includes coating a III-nitride surface having surface roughness features in the micron range with a sacrificial planarization material such as an appropriately chosen photoresist. The sacrificial planarization material is then etched together with the III-nitride roughness features using dry etch methods such as inductively coupled plasma reactive ion etching. By closely matching the etch rates of the sacrificial planarization material and the III-nitride material, a planarized III-nitride surface is achieved. The etch-back process together with a high temperature annealing process yields a planarized III-nitride surface with surface roughness features reduced to the nm range. Planarized III-nitride, e.g., GaN, substrates and devices containing them are also provided.

主权项

1. A substrate comprising:
a first layer, the first layer having roughness features deviating from a surface plane; and a sacrificial layer covering the roughness features, the sacrificial layer having an essentially planar surface, wherein the first layer responds to a first etching method at a first etch rate, the sacrificial layer responds to the first etching method at a second etch rate, and the ratio of the second etch rate to the first etch rate is in the range of 0.2 to 1.2.