Crystalline Si accounts for more than 90% of the solar cells
produced today and about 95% of those cells are fabricated on
p-type Si [1]. This is because of the well-established technology
and equipment base for p-type cell fabrication and lower wafer
and cell processing cost compared to n-type cells.However,p-type
wafers generally have lower bulk life time and are more
suscep-tible to metal impurities compared to then-type wafers [2,3]. It
has been reported that the minority carrier life time in p-type Si is
frequently limited by iron related defects [2,4] with larger electron
capture cross section compared to hole [5]. Iron is often present in
the feed stock material and can be introduced during processing
[6]. There fore,majority of the PV industry currently uses POCl3
diffusion to remove metal impurities including iron [7–11]. POCl3
gettering is attributed to the formation of misfit dislocations on
the surface which provide the sink for impurity gettering.In addition, higher phosphorus surface concentration enhances
gettering because it increases solid solubility and segregation
coefficient of metal impurities [7–17]. The phosphorus ion-im-
planted emitter has recently shown higher performance due to insitu oxide passivation during the implant annealing process
[18,19]. However, its gettering quality is not fully understood and
compared with POCl3 diffusion. This paper conducts a systematic
and controlled study to compare the impact of phosphorus
ion-implantation and POCl3 diffusion induced gettering on
castquasimono and Czochralski(Cz) Si solar cells.
Crystalline Si accounts for more than 90% of the solar cellsproduced today and about 95% of those cells are fabricated onp-type Si [1]. This is because of the well-established technologyand equipment base for p-type cell fabrication and lower waferand cell processing cost compared to n-type cells.However,p-typewafers generally have lower bulk life time and are more suscep-tible to metal impurities compared to then-type wafers [2,3]. Ithas been reported that the minority carrier life time in p-type Si isfrequently limited by iron related defects [2,4] with larger electroncapture cross section compared to hole [5]. Iron is often present inthe feed stock material and can be introduced during processing[6]. There fore,majority of the PV industry currently uses POCl3diffusion to remove metal impurities including iron [7–11]. POCl3gettering is attributed to the formation of misfit dislocations onthe surface which provide the sink for impurity gettering.In addition, higher phosphorus surface concentration enhancesgettering because it increases solid solubility and segregationcoefficient of metal impurities [7–17]. The phosphorus ion-im-planted emitter has recently shown higher performance due to insitu oxide passivation during the implant annealing process[18,19]. However, its gettering quality is not fully understood andcompared with POCl3 diffusion. This paper conducts a systematicศึกษาควบคุมเพื่อเปรียบเทียบผลกระทบของฟอสฟอรัสและ ฝังไอออนและแพร่ POCl3 เกิด gettering บน castquasimono และเซลล์แสงอาทิตย์ศรี Czochralski(Cz)
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