This paper reports recent progress in 94 GHz InP Gunn device development in our laboratory. High power, high efficiency Gunn diodes working in the 94 GHz millimeter range were made from InP epilayers grown by low pressure metalorganic chemical vapor deposition (LP-MOCVD). High quality InP layers were successfully grown using trimethylindium or triethylindium and phosphine. Non intentionally doped InP layers exhibited net residual donors as low as 8.1013cm-3 with Hall mobility as high as 200000cm 2V-1s-1 and 300000 cm2V-1s-1 (60K) using triethylindium and trimethylindium as indium sources respectively. The ability of LP-MOCVD to grow high purity indium phosphide as required for Gunn effect devices has led to significant improvements in the performances of these devices. The InP Gunn diodes processed using the integral heat sink technique have delivered up to 150 mW CW output power with 3.5% efficiency at 94 GHz. Aging tests performed at 85°C on biased diodes with average CW output power of 80mW have demonstrated typical mean time to failure (MTTF) in excess of 20000 hours.