25 nm pitch GaInAs/InP buried structure: Improvement by calixarene as an electron beam resist and tertiarybutylphosphine as a P source in organometallic vapor phase epitaxy regrowth

To achieve a fine periodic semiconductor structure by electron beam (EB) li thography, calixarene was used as an EB resist. A 25 nm pitch InP pattern w as formed successfully and 40 nm pitch InP structures were achieved with go od reproducibility. A shorter developing time, precise stage motion, accura te control of the widths of lines and spaces, and slight O-2 ashing were im portant to obtain a fine InP pattern by a two-step wet chemical etching pro cess. Furthermore, the fabricated periodic InP pattern was buried in a GaIn As structure by organometallic vapor phase epitaxy. The introduction of ter tiarybutylphosphine as the phosphorus source prevented the fine structure f rom deforming when the temperature was raised and a 25 nm pitch periodic st ructure was buried successfully. (C) 1998 American Vacuum Society. [S0734-2 11X(98)09306-8].