@User usually in cmos processes bjt devices are those that come almost for free by using available wells and diffusions. Current gain is usually very low and quite unpredictable from lot to lot. Process recipes are never tuned for centering that gain parameter. Moreover particular care must be taken in the layout to avoid excessive substrate injection for latchup issues. I have seen pnp transistors mostly used as diodes (collector and base tied to 0V) for bandgap voltage references. This is just my experience in memories design on cmos processes.