High voltage operation (> 80 V) of GaN bipolar junction transistors with low leakage

We have demonstrated the high voltage operation of n-p-n GaN bipolar juncti on transistors using regrown emitters. Devices were grown by metalorganic c hemical vapor deposition on sapphire substrates. The n-type emitter was gro wn selectively on a base-collector p-n junction diode using a dielectric ma sk. A thin base (1000 A) was used to increase the current gain over our pre vious result with a regrown emitter [J. B. Limb, L. McCarthy, P. Kozodoy, H . Xing, J. Ibbetson, Y. Smorchkova, S. P. DenBaars, and U. K. Mishra, Elect ron. Lett. 35, 19 (1999)]. The base contacts were better than expected desp ite the use of a thin base. Common emitter operation showing a voltage oper ation of over 80 V with negligible leakage has been demonstrated. Room temp erature current gain was similar to 3 corresponding to a current transfer r atio of similar to 0.75. This results in a calculated minority carrier life time of about 80 pS in the base. (C) 2000 American Institute of Physics. [S 0003-6951(00)04117-6].