One passivating scheme for rear surface of double sided buried contact silicon solar cells which has both experimentally and theoretically demonstrated better passivation than either oxide or back surface field [1] is floating junction passivation. This scheme despite its successful implementation has many processing difficulties. Beside difficulty in the diffusion of a uniform junction at the rear of the device, many hardly avoidable shunting effects during processing steps makes this structure not very promising for commercial production. One successfully implemented scheme which has same benefits of floating junction without associated processing difficulties is using beta emitter material at the back surface for generating enough carries in proper depth to produce an effective low back surface recombination velocity for preventing back surface recombination loss. A very thin layer of a beta emitter material is shown can generate enough carries close to rear surface to compensate for the loss of minority carries from back surface. This scheme is not only suited to double sided buried contact silicon solar cells but also to single sided and laboratory high efficiency solar cells. The improvement in surface passivation for commercial cells is an especially critical issue in achieving lower cost solar cells through reducing substrate thickness while simultaneously increasing efficiency [2]. Using Beta emitters for rear surface passivation of silicon solar cells has numerous advantages over FJ. Despite the many theoretical advantages of FJ passivation, its applicability has been limited by the unavoidable parasitic effects during processing of these cells in commercial production. The objective of this paper is to present a comparative analysis of beta emitter and FJ passivation schemes and to demonstrate effectiveness of the former. Experimental evidence as well as theoretical modelling demonstrates that a beta emitter passivated solar cell has both higher performance and less sensitivity to processing conditions.