The Santa Clara County Housing Trust have probably the best 1st time buyer assistance programs in the state. Their 3 programs provide significant help.
For example. The MAP program requires just 3% down from the buyer who gets a normal 80 1st mortgage. The Trust then provides a 17% 2nd mortgage at only 1% more than the 80% one from the Bank. The PAL and GAP programs provide down payment assistance in specific areas of San Jose and Santa Clara County.
If you want more info drop me an e-mail (email@example.com)l or Google Housing Trust of Santa Clara.