SiC Diodes in the 300 to 1200V range have steadily increased their market penetration in the last 7 years. Especially the 600V SiC diodes are a nearly mandatory device for further increase of power density in modern switch mode power supplies. Those devices entered the market from the high end side due to the still significant higher costs in comparison with conventional fast Si diodes. On the other hand, these high end markets like server or telecom power supplies also require very high reliability of the devices used. In previous papers we showed, that Merged-PN-Schottky (MPS) diodes can be designed for avalanche ruggedness [1,2]. In this paper we will describe, how this feature supports overall reliability improvement. Addditionally, we will show, how a conventional SiC Schottky diode without MPS structure can be modified in order to achieve stable avalanche breakdown in combination with strong reliability improvement.