Post-growth Zn diffusion into InGaAs/InP in a LP-MOVPE reactor

MOVPE based Zn contact diffusion into InGaAs using DMZn as source material was investigated. Maximum hole densities above 1*1020 cm-3 could reproducibly be attained. To achieve this, the presence of an appropriate concentration of AsH3 during diffusion proved to be of crucial importance. The Zn incorporation was found to exponentially increase with decreasing diffusion temperature until Zn3As2 starts to deposit on the wafer at approximately 500 degrees C. Due to the use of wafer rotation excellent lateral diffusion uniformity as characterized by sheet resistance measurements was obtained. The MOVPE based diffusion process features several advantages which make this method superior to existing techniques.